Fluid control apparatus and electronic apparatus

ABSTRACT

A fluid control apparatus includes a flow-path space forming portion, an inflow opening, an outflow opening, and a drive mechanism. The flow-path space forming portion includes a flexible portion that have flexibility, and a facing portion that faces the flexible portion, the flow-path space forming portion forming a flow path space between the flexible portion and the facing portion, the flow path space being a flow path of fluid. The inflow opening is provided to an outer peripheral portion of the flow path space, as viewed from a facing direction in which the flexible portion and the facing portion face each other, the inflow opening being an opening through which the fluid flows into the flow path space. The outflow opening is provided to a portion, in the outer peripheral portion of the flow path space, that is different from a portion, in the outer peripheral portion of the flow path space, that is provided with the inflow opening, as viewed from the facing direction, the outflow opening being an opening through which the fluid flows out of the flow path space. The drive mechanism bends the flexible portion to increase or decrease the volume of the flow path space. Further, the flexible portion is configured such that at least a portion of a region of the flexible portion is curved toward the facing portion to have a concave shape in a reference state in which the flexible portion is not bent by the drive mechanism, the region of the flexible portion being situated further inward than the outer peripheral portion of the flow path space, as viewed from the facing direction.

TECHNICAL FIELD

The present technology relates to a fluid control apparatus thattransfers fluid, and an electronic apparatus.

BACKGROUND ART

For example, a diaphragm-type pump that uses a diaphragm has been putinto practical use as a small and thin pump (for example, refer toPatent Literature 1). The diaphragm-type pump includes a pump room ofwhich the volume varies due to a diaphragm being bent to be deformed,and enables fluid to be intaken into the pump room by increasing thevolume of the diaphragm-type pump, and enables fluid to be dischargedfrom the pump room by decreasing the volume of the diaphragm-type pump.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No.2011-256741

DISCLOSURE OF INVENTION Technical Problem

With respect to fluid control apparatuses as disclosed in PatentLiterature 1, there is a need for a technology that makes it possible toprovide a smaller fluid control apparatus that exhibits a higherperformance.

In view of the circumstances described above, it is an object of thepresent technology to provide a small fluid control apparatus thatexhibits a high performance, and an electronic apparatus that uses thefluid control apparatus.

Solution to Problem

In order to achieve the object described above, a fluid controlapparatus according to an embodiment of the present technology includesa flow-path space forming portion, an inflow opening, an outflowopening, and a drive mechanism.

The flow-path space forming portion includes a flexible portion thathave flexibility, and a facing portion that faces the flexible portion,the flow-path space forming portion forming a flow path space betweenthe flexible portion and the facing portion, the flow path space being aflow path of fluid.

The inflow opening is provided to an outer peripheral portion of theflow path space, as viewed from a facing direction in which the flexibleportion and the facing portion face each other, the inflow opening beingan opening through which the fluid flows into the flow path space.

The outflow opening is provided to a portion, in the outer peripheralportion of the flow path space, that is different from a portion, in theouter peripheral portion of the flow path space, that is provided withthe inflow opening, as viewed from the facing direction, the outflowopening being an opening through which the fluid flows out of the flowpath space.

The drive mechanism bends the flexible portion to increase or decreasethe volume of the flow path space.

Further, the flexible portion is configured such that at least a portionof a region of the flexible portion is curved toward the facing portionto have a concave shape in a reference state in which the flexibleportion is not bent by the drive mechanism, the region of the flexibleportion being situated further inward than the outer peripheral portionof the flow path space, as viewed from the facing direction.

The flexible portion may be configured such that a center portion of theflexible portion as viewed from the facing direction is curved towardthe facing portion to have a concave shape in the reference state.

The flexible portion may have a shape obtained by a plate member beingdeformed and curved toward the facing portion to have a concave shape inthe reference state.

the drive mechanism may bend the flexible portion such that a concaveportion of the flexible portion in the reference state is moved by alargest distance in the facing direction.

The drive mechanism may include a piezoelectric element that isconnected to a certain surface of the flexible portion that is situatedopposite to another surface of the flexible portion that faces thefacing portion.

When the flexible portion is a first flexible portion, the facingportion may be a second flexible portion that has flexibility. In thiscase, the drive mechanism may bend the second flexible portion. Further,the second flexible portion may be configured such that at least aportion of a region of the second flexible portion is curved toward thefirst flexible portion to have a concave shape in the reference state,the region of the second flexible portion being situated further inwardthan the outer peripheral portion of the flow path space, as viewed fromthe facing direction.

The first flexible portion and the second flexible portion may beconfigured to resonate with each other.

The drive mechanism may include a first piezoelectric element that isconnected to a certain surface of the first flexible portion that isopposite to another surface of the first flexible portion that faces thesecond flexible portion, and a second piezoelectric element that isconnected to a certain surface of the second flexible portion that isopposite to another surface of the second flexible portion that facesthe first flexible portion. In this case, the drive mechanism may beconfigured such that a resonance frequency of the entirety of the firstflexible portion and the first piezoelectric element is closer to aresonance frequency of the entirety of the second flexible portion andthe second piezoelectric element.

when the flexible portion is a first flexible portion, the facingportion may be a second flexible portion that has flexibility. In thiscase, the first flexible portion and the second flexible portion may beconfigured to resonate with each other.

The drive mechanism may include a piezoelectric element that isconnected to a certain surface of the first flexible portion that issituated opposite to another surface of the first flexible portion thatfaces the second flexible portion. In this case, the drive mechanism maybe configured such that a resonance frequency of the second flexibleportion is closer to a resonance frequency of the entirety of the firstflexible portion and the first piezoelectric element.

The second flexible portion may have a larger thickness than the firstflexible portion.

The second flexible portion may be configured such that the at least theportion of the region of the second flexible portion is curved towardthe first flexible portion to have a concave shape in the referencestate, the region of the second flexible portion being situated furtherinward than the outer peripheral portion of the flow path space, asviewed from the facing direction.

The flexible portion may include a groove that is formed near an outerperipheral portion of the flexible portion, as viewed from the facingdirection.

The drive mechanism may include a piezoelectric element that isconnected to a certain surface of the flexible portion that is situatedopposite to another surface of the flexible portion that faces thefacing portion. In this case, the groove may be formed at a positionbased on an outer peripheral portion of the piezoelectric element, asviewed from the facing direction.

The fluid control apparatus may further include an inlet, an intakespace forming portion, an outlet, and a discharge space forming portion.

The fluid is intaken into the fluid control apparatus though the inlet.

The intake space forming portion forms an intake space through which theinlet and the inflow opening communicate with each other.

The fluid is discharged from the fluid control apparatus through theoutlet.

The discharge space forming portion forms a discharge space throughwhich the outlet and the outflow opening communicate with each other.

The flow-path space forming portion may include a first plate memberthat is made of a metallic material and includes the flexible portion ina center region of the first plate member, as viewed from the facingdirection, a second plate member that is made of a metallic material andincludes the facing portion in a center region of the second platemember, as viewed from the facing direction, and a spacer member thathas a specified thickness and includes an opening in a center region ofthe spacer member, as viewed from the facing direction, the spacermember being arranged between the first plate member and the secondplate member, the spacer member being joined to the first plate memberand to the second plate member using diffused junction.

The spacer member may include an inlet opening that is configured tocommunicate with an outer peripheral portion of the center opening, andan outlet opening that is configured to communicate with the outerperipheral portion of the center opening, the outlet opening beingprovided to a portion, in the spacer member, that is different from aportion, in the spacer member, that is provided with the inlet opening.

An inlet through which the fluid is intaken into the fluid controlapparatus may be formed in at least one of a region, in the first platemember, that covers the inlet opening, or a region, in the second platemember, that covers the inlet opening. In this case, an outlet throughwhich the fluid is discharged from the fluid control apparatus may beformed in at least one of a region, in the first plate member, thatcovers the outlet opening, or a region, in the second plate member, thatcovers the outlet opening.

An electronic apparatus according to an embodiment of the presenttechnology includes the fluid control apparatus.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a fluid control apparatus according to afirst embodiment, as viewed from diagonally above on the left.

FIG. 2 is a top view of the fluid control apparatus as viewed fromabove.

FIG. 3 is a set of cross-sectional views along the line A-A illustratedin FIG. 2 .

FIG. 4 schematically illustrates an example of a configuration of adrive mechanism.

FIG. 5 schematically illustrates an example of a method for connecting apiezoelectric element to an upper surface member.

FIG. 6 is a set of schematic diagrams used to describe an initialvolume.

FIG. 7 is a top view of a fluid control apparatus according to a secondembodiment, as viewed from above.

FIG. 8 is a cross-sectional view along the line B-B illustrated in FIG.7 .

FIG. 9 individually illustrates respective members that are included inthe fluid control apparatus.

FIG. 10 is a set of schematic diagrams used to describe a method forproducing the fluid control apparatus.

FIG. 11 schematically illustrates an example of a method for connectinga first piezoelectric element to a first flexible portion and connectinga second piezoelectric element to a second flexible portion.

FIG. 12 schematically illustrates an example of a flow of fluid upon apumping operation.

FIG. 13 is a set of schematic diagrams used to describe an initialvolume.

FIG. 14 is a set of tables used to describe the initial volume.

FIG. 15 schematically illustrates examples of a configuration of a fluidcontrol apparatus according to a third embodiment.

FIG. 16 schematically illustrates examples of a configuration of a fluidcontrol apparatus according to other embodiments.

MODE(S) FOR CARRYING OUT THE INVENTION

Embodiments according to the present technology will now be describedbelow with reference to the drawings.

First Embodiment Example of Configuration of Fluid Control Apparatus

An example of a configuration of a fluid control apparatus according toa first embodiment of the present technology is described.

A fluid control apparatus 1 is a diaphragm-type fluid control apparatus,and serves as a pump that can intake and discharge fluid.

Note that examples of the fluid include gas, liquid, and other types offluid, and the fluid is not particularly limited.

In the following description, an X direction in the figure is referredto as a right-and-left direction (a side toward which an arrow of the Xdirection is oriented is referred to as a left side, and the oppositeside is referred to as a right side), a Y direction in the figure isreferred to as a depth direction (a side toward which an arrow of the Ydirection is oriented is referred to as a front side, and the oppositeside is referred to as a back side), and a Z direction in the figure isreferred to as an up-and-down direction (a side toward which an arrow ofthe Z direction is oriented is referred to as an upper side, and theopposite side is referred to as a lower side), in order to facilitateunderstanding of the description.

Of course, an orientation and the like of the fluid control apparatus 1in use are not limited.

FIG. 1 is a perspective view of the fluid control apparatus 1 as viewedfrom diagonally above on the left.

FIG. 2 is a top view of the fluid control apparatus 1 as viewed fromabove.

FIG. 3 is a set of cross-sectional views along the line A-A illustratedin FIG. 2 .

Note that an internal configuration of the fluid control apparatus 1 isindicated by a dashed line in FIG. 2 . Further, an illustration of adrive mechanism 5 illustrated in FIG. 3 is omitted in FIGS. 1 and 2 .

As illustrated in FIGS. 1 to 3 , the fluid control apparatus 1 includesa flow-path space forming portion 2, an inflow opening 3, an outflowopening 4, and the drive mechanism 5.

The flow-path space forming portion 2 forms a flow path space S1 that isa flow path of fluid F.

Note that the space forming portion in the present disclosure includes apart that forms a space (a part that is in contact with a space), and amember that includes the part. It is assumed that, for example, aplurality of partition walls is connected to a single member topartition the member and this results in forming a plurality of spacesobtained by the partitioning. In this case, the single member to whichthe plurality of partition walls is connected serves as a space formingportion for each of the plurality of spaces.

In other words, the single member may be shared to be used as the spaceforming portion forming the plurality of spaces.

In the present embodiment, the flow-path space forming portion 2 has anapproximate outer shape of a cylinder, and the flow path space S1 isformed inside of the flow-path space forming portion 2, as illustratedin FIGS. 1 to 3 .

Specifically, the flow-path space forming portion 2 includes an uppersurface member 6, a lower surface member 7, and spacer members 8 a and 8b. An internal space that is surrounded by the upper surface member 6,the lower surface member 7, and the spacer members 8 a and 8 b is theflow path space S1.

It can also be said that the flow path space S1 is a pump room thatgenerates pressure internally to exert a pump function on the fluid F.

The upper surface member 6 is a member in the form of a circular platethat has a circular outer shape, as viewed from the up-and-downdirection (the Z direction). The upper surface member 6 includes aflexible member.

The lower surface member 7 is a member in the form of a circular platethat has a circular outer shape, as viewed from the up-and-downdirection.

The lower surface member 7 has an outer shape that is identical to theouter shape of the upper surface member 6, as viewed from theup-and-down direction.

Further, the lower surface member 7 is arranged to face the uppersurface member 6 in the up-and-down direction. Thus, the up-and-downdirection (the Z direction) corresponds to a facing direction in whichthe upper surface member 6 and the lower surface member 7 face eachother.

The spacer members 8 a and 8 b are arranged between the upper surfacemember 6 and the lower surface member 7.

As illustrated in FIG. 2 , as viewed from the up-and-down direction, thespacer member 8 a is arranged in a region included in a peripheral edgeregion 10 a for semicircular portions of the upper surface member 6 andthe lower surface member 7 and other than a region included in theperipheral edge region 10 a and situated between a position P1 and aposition P2, the semicircular portion being situated in back, theposition P1 being on a diameter that extends in the X direction, theposition P2 being obtained by the position P1 being offset backward.

Further, as viewed from the up-and-down direction, the spacer member 8 bis arranged in a region included in a peripheral edge region 10 b forsemicircular portions of the upper surface member 6 and the lowersurface member 7 and other than a region included in the peripheral edgeregion 10 b and situated between the position P1 and a position P3, thesemicircular portion being situated in front, the position P1 being onthe diameter extending in the X direction, the position P3 beingobtained by the position P1 being offset forward.

Thus, as viewed from the up-and-down direction, the spacer members 8 aand 8 b are arranged in the regions respectively included in theperipheral edge regions 10 a and 10 b and other than the region situatedbetween the position P1 and a certain position (P2) and the regionsituated between the position P1 and another position (P3), theperipheral edge regions 10 a and 10 b corresponding to all of theperiphery of a circular shape corresponding to the upper surface member6 and the lower surface member 7, the position P1 being on the diameterextending in the X direction, the certain position being obtained by theposition P1 being offset backward, the other position being obtained bythe position P1 being offset forward.

The inflow opening 3 is an opening used to cause the fluid F to flowinto the flow path space S1. As illustrated in FIG. 2 , the inflowopening 3 is provided to an outer peripheral portion 11 of the flow pathspace S1, as viewed from the up-and-down direction. The inflow opening 3is an opening through which a space external to the flow-path spaceforming portion 2 communicates with the flow path space S1.

In the present embodiment, a gap between a right end 12 a of the spacermember 8 a and a right end 13 a of the spacer member 8 b is formed asthe inflow opening 3.

The outflow opening 4 is an opening used to cause the fluid F to flowout of the flow path space S1. As illustrated in FIG. 2 , the outflowopening 4 is provided to a portion, in the outer peripheral portion 11of the flow path space S1, that is different from a portion, in theouter peripheral portion 11 of the flow path space S1, that is providedwith the inflow opening 3, as viewed from the up-and-down direction.Likewise, the outflow opening 4 is an opening through which the spaceexternal to the flow-path space forming portion 2 communicates with theflow path space S1.

In the present embodiment, a gap between a left end 12 b of the spacermember 8 a and a left end 13 b of the spacer member 8 b is formed as theoutflow opening 4.

Thus, the inflow opening 3 and the outflow opening 4 are configured toface each other in the X direction.

Note that positions of the inflow opening 3 and the outflow opening 4,the number of inflow openings 3, the number of outflow openings 4,shapes of the inflow opening 3 and the outflow opening 4, and the likeare not limited, and may be designed discretionarily. For example, aplurality of inflow openings 3 and a plurality of outflow openings 4 maybe formed.

Further, as illustrated in FIG. 3 , the upper surface member 6 isconfigured such that at least a portion of a region of the upper surfacemember 6 is curved toward the lower surface member 7 to have a concaveshape in a reference state, the region of the upper surface member 6being situated further inward than the outer peripheral portion 11 ofthe flow path space S1, as viewed from the up-and-down direction.

In other words, the upper surface member 6 is configured such that atleast a portion of an inward region of the upper surface member 6 iscurved toward the lower surface member 7 to have a concave shape, asviewed from the up-and-down direction.

Note that the reference state is a state in which the upper surfacemember 6 is not bent by the drive mechanism 5 described later. In otherwords, the reference state is a state in which an operation of bendingthe upper surface member 6 is not performed by the drive mechanism 5. Itcan also be said that the reference state is a state in which the fluidcontrol apparatus 1 is not driven.

In the present disclosure, the state of having a concave shape includes,for example, a state in which a pressing force is applied to a certainpoint on the surface of a member and the member itself is deformed tohave a concave shape. For example, the state of having a concave shapeincludes a state in which a plate member is deformed to have a concaveshape by pressing being performed on a certain point on the platemember.

Further, the state of having a concave shape also includes a state inwhich a portion of a region on the surface of a member has a concaveshape and is a hole portion. Moreover, the state of having a concaveshape includes any states that can be referred to as a state of beingcurved toward a facing member to have a concave shape.

Further, the state in which the upper surface member 6 is curved towardthe lower surface member 7 to have a concave shape, as illustrated inFIG. 3 , can also be referred to as a state in which a facing distanceof at least a portion of the inward region of the upper surface member 6to the lower surface member 7 is smaller than a facing distance of anouter peripheral portion of the upper surface member 6 to the lowersurface member 7.

For example, it is also conceivable that the facing distance could bereduced in a curved manner from the outer peripheral portion of theupper surface member 6 to a portion of the upper surface member 6 inwhich the facing distance is smallest (a portion that is situated mostclosely to the lower surface member 7), as in the case of thecross-sectional views illustrated in FIG. 3 .

Further, it is also conceivable that only a portion of the inward regionof the upper surface member 6 could be formed closely to the lowersurface member 7.

The facing distance between the upper surface member 6 and the lowersurface member 7 can also be referred to as a height of a flow path ofthe fluid F.

The state, in the present embodiment, in which the upper surface member6 is curved toward the lower surface member 7 to have a concave shapecan also be referred to as a state in which the flow path height in atleast a portion of the inward region of the upper surface member 6 issmaller than the flow path height in the outer peripheral portion of theupper surface member 6.

In the present embodiment, the upper surface member 6 is configured suchthat a center portion 15 of the upper surface member 6 as viewed fromthe up-and-down direction is curved toward the lower surface member 7 tohave a concave shape in the reference state. In other words, in thereference state, the upper surface member 6 that is a plate member has ashape obtained by the center portion 15 being deformed and curved towardthe lower surface member 7 to have a concave shape.

Thus, the flow path space S1 is a space that has a shape of a cylinderof which an upper surface (a surface in contact with the upper surfacemember 6) is curved downward to have a concave shape in the referencestate.

Note that a shape of the flow path space S1 serving as a pump room isnot limited. For example, any shape such as a shape of a circle(including a perfect circle and an ellipse) or a polygonal shape asviewed from the up-and-down direction may be adopted. For example, whenthe upper surface member is curved toward the lower surface member tohave a concave shape, this can provide an embodiment of the fluidcontrol apparatus 1 according to the present technology.

As illustrated in FIG. 3 , the drive mechanism 5 bends the upper surfacemember 6 to increase or decrease the volume of the flow path space S1.

In the present embodiment, the drive mechanism 5 is configured such thatthe upper surface member 6 being curved toward the lower surface member7 to have a concave shape, is bent downward and upward. Further, thedrive mechanism 5 is configured such that the upper surface member 6 isperiodically bent downward and upward to cause the upper surface member6 to oscillate in the up-and-down direction.

In the present embodiment, the upper surface member 6 is bent such thatthe center portion 15 corresponding to a concave portion of the uppersurface member 6 (a portion in which the facing distance is smallest) inthe reference state is moved by a largest distance in the up-and-downdirection.

A of FIG. 3 illustrates the reference state in which the upper surfacemember 6 is not bent. The reference state can also be a state in whichvoltage is not applied to a piezoelectric element 17.

As illustrated in B of FIG. 3 , the upper surface member 6 is bentdownward. This results in a decrease in the volume of the flow pathspace S1. The volume becomes smallest when the center portion 15 of theupper surface member 6 is moved most downward (hereinafter referred toas a minimum volume state).

As illustrated in C of FIG. 3 , the upper surface member 6 is bentupward from the reference state. This results in an increase in thevolume of the flow path space S1. Then, the volume becomes largest whenthe center portion 15 of the upper surface member 6 is moved most upward(hereinafter referred to as a maximum volume state).

The upper surface member 6 is bent from the reference state illustratedin A of FIG. 3 , and the maximum volume state and the minimum volumestate are periodically caused repeatedly. This results in providing apump function. Accordingly, the fluid F flowing into the flow path spaceS1 through the inflow opening 3 can flow out of the flow path space S1through the outflow opening 4.

FIG. 4 schematically illustrates an example of a configuration of thedrive mechanism 5.

In the present embodiment, the drive mechanism 5 includes thepiezoelectric element 17 and a drive controller 18, as illustrated inFIG. 4 .

The piezoelectric element 17 is connected to an upper surface 20 of theupper surface member 6 that is situated opposite to a lower surface 19of the upper surface member 6 that faces the lower surface member 7. Thepiezoelectric element 17 is circular as viewed from the up-and-downdirection, and is connected to a circular region of the upper surfacemember 6 that covers the flow path space S1.

The drive controller 18 applies voltage (an alternate-current (AC)voltage) in the form of a drive signal to the piezoelectric element 17through, for example, wiring. A specific configuration of the drivecontroller 18 is not limited, and, for example, any circuitconfiguration may be adopted.

The piezoelectric element 17 is an element that enableselectromechanical conversion. The piezoelectric element 17 enables theupper surface member 6 to be bent by expanding and contracting inresponse to voltage being applied.

The use of the piezoelectric element makes it possible to provideoscillation in a high frequency band with a high degree of ability torespond. In other words, it becomes possible to increase and decreasethe volume of the flow path space S1 repeatedly at a very high speed,the increase and decrease causing a relatively small amount of variationin the volume of the flow path space S1. This results in being able toimprove output (a pressure) of a pump, and thus to provide a high-levelpump function.

In the present embodiment, a diaphragm 22 is implemented by the uppersurface member 6 and the piezoelectric element 17.

Note that the configuration of the drive mechanism 5 is not limited tothe configuration in which the piezoelectric element 17 is used. Forexample, a configuration in which, for example, a dielectric elastomeris used or a configuration in which solenoid is used may be adopted.

[Size]

The fluid control apparatus 1 of a diaphragm type is used in the presentembodiment. This provides an advantage in, for example, making the fluidcontrol apparatus 1 smaller.

For example, it is possible to provide the upper surface member 6 andthe lower surface member 7 each having a size in which a diameter isabout 10 mm and a thickness is about 1 mm. Further, designing can alsobe performed such that a reference facing distance between the uppersurface member 6 and the lower surface member 7 is about 100 μm. Notethat the reference facing distance corresponds to a facing distancebefore the upper surface member 6 is formed to have a concave shape, andcan also be a facing distance in the outer peripheral portion 11 of theupper surface member 6.

Designing can be performed such that an amount of concave (an amount ofdeformation) of the upper surface member 6 is, for example, 10 μm to 80μm. Note that the amount of concave is an amount of downward deformationof the center portion 15 from a state before the deformation, the centerportion 15 being situated most closely to the lower surface member 7. Inother words, it is possible to perform designing such that the centerportion 15 situated most closely to the lower surface member 7 getscloser to the lower surface member 7 at a distance of 20 μm to 90 μm.

Of course, the size is not limited to being designed as described above,and the adoption of any size makes it possible to provide an embodimentof the fluid control apparatus 1 according to the present technology.

Note that it is desirable that the upper surface member 6 not be broughtinto contact with the lower surface member 7 in the minimum volume stateillustrated in B of FIG. 3 .

[Material]

In the present embodiment, a metallic material such as stainless orAlloy 42 is used for the upper surface member 6, the lower surfacemember 7, and the spacer members 8 a and 8 b. Of course, any othermetallic material may be used. Further, any material, such as a plasticmaterial, that is other than a metallic material may be used.

The upper surface member 6, the lower surface member 7, and the spacermembers 8 a and 8 b may be made of different materials. Further, aportion of the upper surface member 6 that is connected to the spacermembers 8 a and 8 b, and a portion of the upper surface member 6 that isin contact with the flow path space S1 may be made of differentmaterials. In other words, a portion of the upper surface member 6 thatis bent in order to increase and decrease the volume of the flow pathspace S1, and a portion of the upper surface member 6 that is connectedto the spacer members 8 a and 8 b may be made of different materials.

For example, as viewed from the up-and-down direction, a region thatcorresponds to the outer peripheral portion of the upper surface membermay be made of a metallic material, and the inward region of the uppersurface member may be made of a plastic material.

[Production Method]

First, the upper surface member 6, the lower surface member 7, and thespacer members 8 a and 8 b, which are made of a metallic material, arecreated by any processing technology such as etching or laserprocessing.

The created upper surface member 6, lower surface member 7, and spacermembers 8 a and 8 b are connected to each other to be stacked in theup-and-down direction.

In the present embodiment, the upper surface member 6, the lower surfacemember 7, and the spacer member 8 a and 8 are stacked with a specifieddegree of accuracy in position and joined by diffused junction. Thismakes it possible to integrally form the flow-path space forming portion2 made of metal.

This results in being advantageous in causing the diaphragm 22 (theupper surface member 6 and the piezoelectric element 17) to oscillate ina high frequency band with a high degree of ability to respond.

A specific method or configuration used to perform processing such asetching and diffused junction is not limited, and, for example, awell-known technology may be used.

Of course, the upper surface member 6, the lower surface member 7, andthe spacer members 8 a and 8 b may be connected to each other by amethod other than diffused junction.

Moreover, any other method such as die casting may be adopted in orderto form the flow-path space forming portion 2.

FIG. 5 schematically illustrates an example of a method for connectingthe piezoelectric element 17 to the upper surface member 6.

As illustrated in A of FIG. 5 , the flow-path space forming portion 2including the upper surface member 6 not having a concave shape(hereinafter referred to as the flow-path space forming portion 2 beforebeing formed to have a concave shape) is placed on a holding fixture 23.The flow-path space forming portion 2 before being formed to have aconcave shape is placed on the holding fixture 23 such that the lowersurface member 7 is in contact with the holding fixture 23.

A specific configuration of the holding fixture 23 is not limited, andany fixture that can hold the flow-path space forming portion 2 beforebeing formed to have a concave shape may be used.

A proper amount of adhesive is applied to the upper surface 20 of theupper surface member 6 before being formed to have a concave shape, andthe piezoelectric element 17 is arranged at an appropriate position. Forexample, an epoxy adhesive or the like can be applied using a methodsuch as dispenser or pad printing. Of course, the method is not limitedthereto.

A pressure fixture 24 is arranged above the flow-path space formingportion 2 before being formed to have a concave shape.

The pressure fixture 24 is circular as viewed from the up-and-downdirection, which is the same as the piezoelectric element 17. Then, aposition of the pressure fixture 24 is determined such that pressure canbe applied to an entire surface of the piezoelectric element 17.

An end portion 25 that is situated on a pressure applying surface of thepressure fixture 24 is made of a flexible material such as a siliconrubber.

As illustrated in B of FIG. 5 , pressure is applied to the piezoelectricelement 17 downward using the pressure fixture 24. Due to pressure beingapplied using the pressure fixture 24, the piezoelectric element 17 andthe upper surface member 6 are deformed and curved toward the lowersurface member 7 to have a concave shape. In this state, processing ofhardening an adhesive is performed.

In the present embodiment, the end portion 25 of the pressure fixture 24is made of a flexible material. Thus, the end portion 25 is deformedfollowing the deformation of the piezoelectric element 17. This makes itpossible to properly apply pressure to the entire surface of thepiezoelectric element 17. Consequently, the piezoelectric element 17 canbe bonded satisfactorily and deformed to have a desired concave shape.

Further, the end portion 25 is made of a flexible material. This alsomakes it possible to accommodate unevenness on the surface of thepiezoelectric element 17, and thus to prevent the piezoelectric element17 from, for example, being broken due to pressure being applied.

A condition for applying pressure using the pressure fixture 24 is notlimited. A condition that enables the upper surface member 6 to bedeformed to have a concave shape, may be set as appropriate. Forexample, a pressure-application force, a pressure-application time, atemperature, and the like may be set as appropriate such that an amountof concave of the upper surface member 6 is a desired amount of concave.

The present embodiment makes it possible to simultaneously bond thepiezoelectric element 17 and deform the upper surface member 6 such thatthe upper surface member 6 has a concave shape, as illustrated in FIG. 5. In other words, when the piezoelectric element 17 is bonded, thisenables the upper surface member 6 to be deformed to have a concaveshape at the same time as the bonding of the piezoelectric element 17.

Thus, there is no need for, for example, a particular step or aparticular fixture in order to form the upper surface member 6 such thatthe upper surface member 6 has a concave shape. This results in beingable to simplify steps of producing the flow-path space forming portion2, and thus to shorten the time necessary for the production.

Of course, the present technology is not limited to the methodillustrated in FIG. 5 . For example, the upper surface member 6 may beformed to have a concave shape in advance to be connected to the spacermembers 8 a and 8 b. Further, the piezoelectric element 17 may be bondedto the upper surface member 6 formed to have a concave shape in advance.

[Decrease in Initial Volume]

FIG. 6 is a set of schematic diagrams used to describe an initialvolume.

A of FIG. 6 schematically illustrates the flow path space S1 before theupper surface member 6 is formed to have a concave shape.

B of FIG. 6 schematically illustrates the flow path space S1 in thereference state.

C of FIG. 6 schematically illustrates the flow path space S1 duringdriving a pump.

As illustrated in A of FIG. 6 , the upper surface member 6 and the lowersurface member 7 are arranged at a reference facing distance H from eachother.

As illustrated in B of FIG. 6 , the upper surface member 6 is curved byan amount of concave Z to have a concave shape. The volume of the flowpath space S1 in the reference state illustrated in B of FIG. 5 isassumed to be an initial volume.

It is assumed that the upper surface member 6 oscillates with anamplitude M by moving from the reference state in the up-and-downdirection, as illustrated in C of FIG. 6 . Further, it is assumed that asmallest facing distance between the upper surface member 6 and thelower surface member 7 in the minimum volume state is a minimum gap Gm.

A rate of volume variation that is represented by a formula indicatedbelow can be used as an indicator used to evaluate a pump function ofintaking the fluid F into the path space S1 and discharging the fluid Ffrom the flow path space S1.

rate of volume variation=amount of volume variation/initial volume  (1)

The amount of volume variation is an amount of variation in the volumeof the flow path space S1 that is caused due to the upper surface member6 being bent, and can be represented by a difference between the minimumvolume and the maximum volume of the flow path space S1. Thus, theamount of volume variation can also be represented by an amount ofdownward/upward deformation (an amount of downward/upward displacement)of the upper surface member 6.

The difference between the minimum volume and the maximum volume of theflow path space S1 is divided by the initial volume to calculate therate of volume variation. A higher rate of volume variation results inproviding a higher-level pump function, and this makes it possible toprovide the fluid control apparatus 1 exhibiting a higher performance.

For example, when an amount of deformation of the upper surface member 6remains unchanged, the rate of volume variation is higher if the initialvolume is smaller. This results in providing a higher-level pumpfunction. For example, the amount of deformation of the upper surfacemember 6 is greatly affected by the area of the piezoelectric element 17connected to the upper surface member 6. Thus, it is important todecrease the initial volume when the area of the piezoelectric element17 remains unchanged.

In the present embodiment, the upper surface member 6 is curved towardthe lower surface member 7 to have a concave shape in the referencestate, as illustrated in B of FIG. 6 . Thus, the initial volume can bedecreased. Therefore, the rate of volume variation can be made higher,as represented by the formula (1). This makes it possible to provide ahigh-level pump function.

For example, the initial volume can also be decreased by making thefacing distance between the upper surface member 6 and the lower surfacemember 7 smaller in a state in which the upper surface member 6 does nothave a concave shape, as illustrated in A of FIG. 6 . However, in thiscase, the facing distance in the inflow opening 3 and the facingdistance in the outflow opening 4 are made smaller in the same way, theinflow opening 3 and the outflow opening 4 being formed in the outerperipheral portion 11 of the flow path space S1. This results inreducing the cross-sectional areas of the inflow opening 3 and theoutflow opening 4. Consequently, flow path resistances are increased atthe inflow opening 3 and the outflow opening 4, and this results inmaking the level of the pump function lower.

In the present embodiment, the reference facing distance H is maintainedin the outer peripheral portion 11 of the flow path space S1, asillustrated in B of FIG. 6 . Thus, the initial volume is decreased in astate in which sufficient flow path heights are maintained at the inflowopening 3 and the outflow opening 4.

This makes it possible to prevent the flow path resistances from beingincreased at the inflow opening 3 and the outflow opening 4. Thisresults in not blocking a flow of the fluid F, that is, this results inbeing able to sufficiently reduce a loss in flow path. Accordingly, ahigh-level pump function can be provided.

Further, when the upper surface member 6 does not have a concave shape,a reaction (a back pressure) to a force that is applied to the uppersurface member 6 in the up-and-down direction greatly acts on theentirety of the upper surface member 6. This results in preventinghigh-speed oscillation (a piston motion), and thus in making the levelof the pump function lower.

In the present embodiment, the center portion 15 of the upper surfacemember 6 is situated most closely to the lower surface member 7, asillustrated in B of FIG. 6 , and the center portion 15 oscillates with alargest amplitude M. On the other hand, there is a small change infacing distance in the outer peripheral portion 11 of the flow pathspace S1, and a portion of the upper surface member 6 that correspondsto the outer peripheral portion 11 of the flow path space S1 oscillateswith a small amplitude.

In other words, in the present embodiment, a very high pressure isgenerated in a center region of the upper surface member 6, whereasgeneration of pressure is suppressed in the outer peripheral portion 11of the flow path space S1. This makes it possible to suppress a reactionthat acts on the entirety of the upper surface member 6, and thusenables high-speed oscillation (a piston motion). This results inproviding a high-level pump function.

For example, it is assumed that a fluid control apparatus is formed in astate in which the upper surface member 6 does not have a concave shapeyet, as illustrated in A of FIG. 5 . This is a comparative example. Inthis case, the amount of deformation of the upper surface member 6remains unchanged. Thus, the amount of volume variation in the formula(1) remains unchanged.

As illustrated in B of FIG. 6 , the upper surface member 6 is formed tohave a concave shape, and then an initial area is reduced. For example,the initial volume is set to 60% of a volume before the upper surfacemember 6 is formed to have a concave shape. In this case, the rate ofvolume variation can be increased about 1.67-fold, which is calculatedusing the formula (1).

As described above, the pump function can be greatly improved by theupper surface member 6 being formed to have a concave shape.

Note that it is favorable that the upper surface member 6 not be broughtinto contact with the lower surface member 7 in the reference stateillustrated in B of FIG. 6 . Thus, it is favorable that “referencefacing distance H>amount of concave Z”. Note that a value obtained by“reference facing distance H−amount of concave Z” corresponds to aminimum distance between the upper surface member 6 and the lowersurface member 7 in the reference state.

Further, it is favorable that, upon driving the fluid control apparatus1, the upper surface member 6 not be brought into contact with the lowersurface member 7 in the minimum volume state.

Thus, it is favorable that “minimum gap Gm>0”, as illustrated in C ofFIG. 5 . Note that the minimum minimum gap Gm is represented by aformula indicated below.

minimum gap Gm=reference facing distance H−amount of concaveZ−(amplitude M/2)  (2)

In other words, it is favorable that the minimum facing distance betweenthe center portion 15 of the upper surface member 6 and the lowersurface member 7 in the reference state illustrated in B of FIG. 5 begreater than ½ of the amplitude in the center portion 15 of the uppersurface member 6 upon driving a pump.

Note that an optimal value of the amount of deformation of the uppersurface member 6 differs depending on a relationship between flexuralrigidity of the piezoelectric element 17, flexural rigidity of the uppersurface member 6, and a force to apply pressure to the piezoelectricelement 17 when the piezoelectric element 17 is bonded. Thus, it is alsoimportant to adjust a pressure-application force in consideration offlexural rigidity of each member.

In the present embodiment, the upper surface member 6 corresponds to anembodiment of a flexible portion having flexibility. Further, the lowersurface member 7 corresponds to an embodiment of a facing portion thatfaces the flexible portion.

Furthermore, the upper surface member 6 also corresponds to anembodiment of a first plate member that is made of a metallic materialand includes the flexible portion in a center region of the first platemember. In the present embodiment, an entire region including the centerregion is the flexible portion.

Further, the lower surface member 7 also corresponds to an embodiment ofa second plate member that is made of a metallic material and includesthe facing portion in a center region of the second plate member. In thepresent embodiment, an entire region including the center region is thefacing portion.

The spacer members 8 a and 8 b correspond to an embodiment of a spacermember that has a specified thickness and includes an opening in acenter region of the spacer member. The spacer member is arrangedbetween the first plate member and the second plate member and joined tothe first plate member and to the second plate member using diffusedjunction. The opening in the center region corresponds to a portioncorresponding to the flow path space S1.

The flow-path space forming portion 2 includes the flow path space S1between the flexible portion and the facing portion.

The drive mechanism 5 bends the flexible portion to increase anddecrease the volume of the flow path space S1.

The inflow opening 3 illustrated in, for example, FIG. 2 may be used asan inlet used to intake the fluid F into the fluid control apparatus 1.Further, the outflow opening 4 may be used as an outlet used todischarge the fluid F from the fluid control apparatus 1.

Further, the inlet and the outlet may be respectively formed separatelyfrom the inflow opening 3 and the outflow opening 4. In this case, forexample, an intake space forming portion that forms an intake spacethrough which the inlet and the inflow opening 3 communicate with eachother may be further formed. The intake space is a space used to lead,to the inflow opening 3, the fluid F intaken from the inlet. Further, adischarge space forming portion that forms a discharge space throughwhich the outlet and the outflow opening 4 communicate with each othermay be further formed. The discharge space is a space used to lead, tothe outlet, fluid flowing out of the outflow opening 4.

A high-level pump function can also be provided in the flow path spaceS1 when the intake space and the discharge space described above areformed. This makes it possible to provide a small fluid controlapparatus 1 exhibiting a high performance.

[Resonance Configuration]

The lower surface member 7 is formed as a flexible member. Further, theflow-path space forming portion 2 can also be configured such that theupper surface member 6 and the lower surface member 7 resonate with eachother.

The amount of volume variation in the formula (1) can be increased bythe upper surface member 6 and the lower surface member 7 resonatingwith each other. This makes it possible to improve the pump function.

A configuration in which the upper surface member 6 and the lowersurface member 7 resonate with each other may be hereinafter referred toas a resonance configuration. Further, improving the pump function bythe upper surface member 6 and the lower surface member 7 resonatingwith each other may be referred to as a resonance effect.

Note that the lower surface member 7 also serves as a diaphragm when theresonance configuration is adopted. A diaphragm implemented by the uppersurface member 6 and the piezoelectric element 17 may be referred to asa first diaphragm, and a diaphragm implemented by the lower surfacemember 6 may be referred to as a second diaphragm.

Causing the upper surface member 6 and the lower surface member 7 toresonate with each other corresponds to causing the first diaphragm andthe second diaphragm to resonate with each other.

For example, the configuration is made such that a resonance frequency(a primary resonance frequency) of the entirety of the upper surfacemember 6 and the piezoelectric element 17 is closer to a resonancefrequency of the lower surface member 7. In other words, theconfiguration is made such that a resonance frequency of the firstdiaphragm is closer to a resonance frequency of the second diaphragm.

Consequently, oscillation of each of the first diaphragm and the seconddiaphragm is maximized at the resonance frequency. This makes itpossible to generate a high pressure in a pump room.

Note that, due to resonance, the first diaphragm (the upper surfacemember 6 and the piezoelectric element 17) and the second diaphragm (thelower surface member 7) are respectively bent upward and downward insynchronization with each other. Further, due to resonance, the firstdiaphragm (the upper surface member 6 and the piezoelectric element 17)and the second diaphragm (the lower surface member 7) are respectivelybent downward and upward in synchronization with each other.

In other words, in synchronization with each other, the two diaphragmsare respectively bent in a direction in which the volume of the flowpath space S1 is increased and in a direction in which the volume of theflow path space S1 is decreased. This results in providing an excellentresonance effect.

Note that the resonance frequency is defined by, for example, a specificgravity, the Young's modulus, a thickness, and a size of a material.When, for example, materials and sizes of the upper surface member 6,the piezoelectric element 17, and the lower surface member 7 aredesigned as appropriate, this makes it possible to cause the resonancefrequencies of the first diaphragm and the second diaphragm to be closerto each other.

For example, the upper surface member 6 is formed using a metallicmaterial such as stainless or Alloy 42. The lower surface member 7 isformed using the same metallic material as the upper surface member 6.Since the piezoelectric element 17 is bonded to the upper surface 20 ofthe upper surface member 6, a resonance frequency of the entirety of thefirst diaphragm is higher than a resonance frequency of the uppersurface member 6 in a state in which the piezoelectric element 17 is notbonded to the upper surface member 6.

A thickness of the lower surface member 7 corresponding to the seconddiaphragm is made larger than a thickness of the upper surface member 6.This enables the resonance frequency of the entirety of the firstdiaphragm (the upper surface member 6 and the piezoelectric element 17)to be closer to the resonance frequency of the second diaphragm (thelower surface member 7). This makes it possible to provide a resonanceconfiguration, and thus to provide a resonance effect.

When the resonance configuration is adopted, the upper surface member 6corresponds to an embodiment of a first flexible portion. Further, thelower surface member 7 corresponds to an embodiment of a second flexibleportion. The resonance configuration corresponds to a structure in whichthe first flexible portion and the second flexible portion resonate witheach other.

For example, it is assumed that an adhesive or the like is used toconnect the upper surface member 6, the spacer members 8 a and 8 b, andthe lower surface member 7. In this case, a loss in transmittingoscillation energy, a deviation of a resonance frequency, and the likeare easily caused. This results in difficulty in providing a resonanceconfiguration.

As in the present embodiment, the upper surface member 6, the spacermembers 8 a and 8 b, and the lower surface member 7 are joined bydiffused junction to integrally form the flow-path space forming portion2 made of metal. This makes it possible to suppress the loss intransmitting oscillation energy, the deviation of a resonance frequency,and the like, and thus to easily provide a resonance configuration.

Further, the adoption of a resonance configuration makes it possible tocirculate oscillation energy generated in the first diaphragm betweenthe first diaphragm and the second diaphragm, and thus to suppress aloss in the oscillation energy. This results in being able to provide ahigh-level pump function.

Of course, the present technology is not limited to being applied whenthe resonance configuration is adopted.

Products using fluid such as gas or liquid are used in variousapplications to, for example, industrial air cylinders, air bags, andcuffs used for blood pressure measurement. The use of fluid force offluid makes it possible to provide new functions such as movement thatis different from movement of actuators in the past, and generation of asense of pressure or a tactile sense using pressure.

There is a need for a device that creates a flow of and a pressure offluid, in order to use the fluid force. For example, pumps and blowers(fans) that have been used in the past have a relatively large size, andthus it is difficult to apply them to small devices and wearabledevices.

The diaphragm-type pump using oscillation generated by the piezoelectricelement is suitable to make an apparatus smaller, and can controlpressure and a flow rate. For example, the diaphragm-type pump can besufficiently applied as a pressure generation source of a cuff used in aportable sphygmomanometer.

It is desirable that a device including a pump function be made smallerin size and exhibit a higher performance, in order to use a fluid forcein the future.

In the present embodiment, the upper surface member 6 arranged in astate in which the flow path space S1 is situated between the uppersurface member 6 and the lower surface member 7 is curved toward thelower surface member 7 to have a concave shape in the reference state.Further, the inflow opening 3 and the outflow opening 4 are formed inthe outer peripheral portion 11 of the flow path space S1. This makes itpossible to provide a smaller fluid control apparatus 1 exhibiting ahigher performance.

Further, the adoption of a resonance configuration makes it possible toachieve a much higher performance.

Second Embodiment

A fluid control apparatus according to a second embodiment of thepresent technology is described. In the following description,descriptions of a configuration and an operation similar to those of thefluid control apparatus 1 described in the embodiment above are omittedor simplified.

FIG. 7 is a top view of a fluid control apparatus 27 according to thesecond embodiment, as viewed from above.

FIG. 8 is a cross-sectional view along the line B-B illustrated in FIG.7 . The line B-B is a line that has a right angle bend in a centerportion 37 of a first resonance plate 29.

FIG. 9 individually illustrates respective members that are included inthe fluid control apparatus 27. Note that an illustration of thepiezoelectric element is omitted in FIG. 9 .

The fluid control apparatus 27 according to the present embodiment hasan approximate outer shape of a quadrangular prism, and the flow pathspace S1, an intake space S2, and a discharge space S3 are formed insideof the fluid control apparatus 27.

The fluid control apparatus 27 includes a first fixation plate 28, thefirst resonance plate 29, a spacer member 30, a second resonance plate31, and a second fixation plate 32. Further, the fluid control apparatus27 includes a first piezoelectric element 33, a second piezoelectricelement 34, and a check valve 35.

As illustrated in FIG. 8 , the first fixation plate 28, the firstresonance plate 29, the spacer member 30, the second resonance plate 31,and the second fixation plate 32 are plate members. Further, asillustrated in FIG. 9 , the members respectively have approximate outershapes of equal rectangles, as viewed from the up-and-down direction. Ina state in which outer edges of the respective members are aligned, themembers are stacked to be connected in the up-and-down direction.

As illustrated in FIG. 8 , the respective members corresponding to thesecond fixation plate 32, the second resonance plate 31, the spacermember 30, the first resonance plate 29, and the first fixation plate 28are stacked upward in this order.

As illustrated in FIG. 9 , the spacer member 30 includes a centeropening 38, two inlet openings 39 a and 39 b, and two outlet openings 40a and 40 b.

The center opening 38 is formed in a center region of the spacer member30, as viewed from the up-and-down direction. Further, the centeropening 38 is circular, as viewed from the up-and-down direction. Thecenter opening 38 is configured such that a center portion of the centeropening 38 coincides with the center portion 37 of the first resonanceplate 29.

The two inlet openings 39 a and 39 b are formed in a diagonal line thatconnects apexes 41 a and 41 c of the spacer member 30 in a state inwhich the center opening 38 is situated between the inlet openings 39 aand 39 b, the apex 41 a being situated in back on the right, the apex 41c being situated in front on the left. Further, the two inlet openings39 a and 39 b are formed to each communicate with an outer peripheralportion 38 a of the center opening 38.

The inlet opening 39 a is formed between the center opening 38 and theapex 41 a to communicate with the center opening 38.

The inlet opening 39 b is formed between the center opening 38 and theapex 41 c to communicate with the center opening 38.

The two outlet openings 40 a and 40 b are formed in a diagonal line thatconnects apexes 41 d and 41 b of the spacer member 30 in a state inwhich the center opening 38 is situated between the outlet openings 40 aand 40 b, the apex 41 d being situated in back on the left, the apex 41b being situated in front on the right. Further, the two outlet openings40 a and 40 b are formed to each communicate with the outer peripheralportion 38 a of the center opening 38.

The outlet opening 40 a is formed between the center opening 38 and theapex 41 d to communicate with the center opening 38.

The outlet opening 40 b is formed between the center opening 38 and theapex 41 b to communicate with the center opening 38.

As illustrated in FIG. 9 , the two inlet openings 39 a and 39 b areformed symmetrically about a center portion of the spacer member 30 (acenter portion of the center opening 38), as viewed from the up-and-downdirection. The two outlet openings 40 a and 40 b are formedsymmetrically about the center portion of the spacer member 30 (thecenter portion of the center opening 38), as viewed from the up-and-downdirection.

Further, the two inlet openings 39 a and 39 b and the two outletopenings 40 a and 40 b have equal shapes, and are each formed to be openin a direction of the center portion of the spacer member 30.

The first resonance plate 29 includes a first flexible portion 42 thathas flexibility, and two outlets 43 a and 43 b.

The first flexible portion 42 is formed in a center region of the firstresonance plate 29, as viewed from the up-and-down direction. Further,the first flexible portion 42 is circular as viewed from the up-and-downdirection.

The first flexible portion 42 is configured such that a center portionof the first flexible portion 42 coincides with the center portion 37 ofthe first resonance plate 29. In other words, it can also be said thatthe center portion 37 is the center portion 37 of the first flexibleportion 42.

Further, the first flexible portion 42 is formed to cover the centeropening 38 of the spacer member 30 from above (to overlap the centeropening 38). Furthermore, the center portion 37 of the first flexibleportion 42 and the center portion of the center opening 38 of the spacermember 30 coincide with each other.

As illustrated in FIG. 8 , the first flexible portion 42 is configuredsuch that at least a portion of a region of the first flexible portion42 is curved toward the second resonance plate 31 to have a concaveshape in the reference state, the region of the first flexible portion42 being situated further inward than the outer peripheral portion 11 ofthe flow path space S1, as viewed from the up-and-down direction.

In the present embodiment, the first flexible portion 42 is configuredsuch that the center portion 37 is curved toward the second resonanceplate 31 to have a concave shape in the reference state, as viewed fromthe up-and-down direction.

The two outlets 43 a and 43 b are formed in a diagonal line thatconnects apexes 45 d and 45 b of the first resonance plate 29 in a statein which the first flexible portion 42 is situated between the outlets43 a and 43 b, the apex 45 d being situated in back on the left, theapex 45 b being situated in front on the right.

The outlet 43 a is formed between the first flexible portion 42 and theapex 45 d. As illustrated in FIG. 7 , the outlet 43 a is formed in aportion that corresponds to a portion inside of the outlet opening 40 aof the spacer member 30, as viewed from the up-and-down direction.

The outlet 43 b is formed between the first flexible portion 42 and theapex 45 b. The outlet 43 b is formed in a portion that corresponds to aportion inside of the outlet opening 40 b of the spacer member 30, asviewed from the up-and-down direction.

The first fixation plate 28 includes a center opening 46 and two outletopenings 47 a and 47 b.

The center opening 46 is formed in a center region of the first fixationplate 28, as viewed from the up-and-down direction. Further, the centeropening 46 is circular as viewed from the up-and-down direction. Thecenter opening 46 is configured such that a center portion of the centeropening 46 coincides with the center portion of the center opening 38 ofthe spacer member 30.

The two outlet openings 47 a and 47 b are formed in a diagonal line thatconnects apexes 48 d and 48 b of the first fixation plate 28 in a statein which the center opening 46 is situated between the outlet openings47 a and 47 b, the apex 48 d being situated in back on the left, theapex 48 b being situated in front on the right.

The outlet opening 47 a is formed between the center opening 46 and theapex 48 d. The outlet opening 47 a has a shape obtained by a rectangularopening and a semicircular opening communicating with each other. Theoutlet opening 47 a is formed such that a portion corresponding to therectangular opening is situated along the center opening 46 and suchthat a top of a portion corresponding to the semicircular opening isoriented toward the apex 48 d.

The outlet opening 47 b is formed between the center opening 46 and theapex 48 db. The outlet opening 47 b has a shape equal to the shape ofthe outlet opening 47 a. The outlet opening 47 b is formed such that aportion corresponding to the rectangular opening is situated along thecenter opening 46 and such that a top of a portion corresponding to thesemicircular opening is oriented toward the apex 48 b.

Further, as illustrated in FIG. 7 , the outlet opening 47 a is formedsuch that the outlet 43 a of the first resonance plate 29 is situatedinside of the outlet opening 47 a, as viewed from the up-and-downdirection. The outlet opening 47 b is formed such that the outlet 43 bof the first resonance plate 29 is situated inside of the outlet opening47 b, as viewed from the up-and-down direction.

Thus, the outlet opening 40 a of the spacer member 30 and the outletopening 47 a of the first fixation plate 28 are formed to overlap eachother, as viewed from the up-and-down direction. Further, the outletopening 40 b of the spacer member 30 and the outlet opening 47 b of thefirst fixation plate 28 are formed to overlap each other.

The second resonance plate 31 includes a second flexible portion 49 thathas flexibility, and two inlets 50 a and 50 b.

The second flexible portion 49 is formed in a center region of thesecond resonance plate 31, as viewed from the up-and-down direction.Further, the second flexible portion 49 is circular as viewed from theup-and-down direction.

The second flexible portion 49 is configured such that a center portionof the second flexible portion 49 coincides with a center portion 51 ofthe second resonance plate 29. In other words, it can also be said thatthe center portion 51 is the center portion 51 of the second flexibleportion 49.

Further, the second flexible portion 49 is formed to cover the centeropening 38 of the spacer member 30 from below (to overlap the centeropening 38). Furthermore, the center portion 51 of the second flexibleportion 49 and the center portion of the center opening 38 of the spacermember 30 coincide with each other.

As illustrated in FIG. 8 , the second flexible portion 49 is configuredsuch that at least a portion of a region of the second flexible portion49 is curved toward the first resonance plate 29 to have a concave shapein the reference state, the region of the second flexible portion 49being situated further inward than the outer peripheral portion 11 ofthe flow path space S1, as viewed from the up-and-down direction.

In the present embodiment, the second flexible portion 49 is configuredsuch that the center portion 51 is curved toward the first resonanceplate 29 to have a concave shape in the reference state, as viewed fromthe up-and-down direction.

In the present embodiment, the first flexible portion 42 of the firstresonance plate 29 and the second flexible portion 49 of the secondresonance plate 31 face each other in the up-and-down direction in astate in which the center opening 38 of the spacer member 30 is situatedbetween the first flexible portion 42 and the second flexible portion49, as illustrated in FIG. 8 .

The first flexible portion 42 is configured such that the center portion37 is curved toward the second flexible portion 49 to have a concaveshape in the reference state. The second flexible portion 49 isconfigured such that the center portion 51 is curved toward the firstflexible portion 42 to have a concave shape in the reference state.

The two inlets 50 a and 50 b are formed in a diagonal line that connectsapexes 52 a and 52 c of the second resonance plate 31 in a state inwhich the second flexible portion 49 is situated between the inlets 50 aand 50 b, the apex 52 a being situated in back on the right, the apex 52c being situated in front on the left.

The inlet 50 a is formed between the second flexible portion 49 and theapex 52 a. As illustrated in FIG. 7 , the inlet 50 a is formed in aportion that corresponds to a portion inside of the inlet opening 39 aof the spacer member 30, as viewed from the up-and-down direction.

The inlet 50 b is formed between the second flexible portion 49 and theapex 52 c. The inlet 50 b is formed in a portion that corresponds to aportion inside of the inlet opening 39 b of the spacer member 30, asviewed from the up-and-down direction.

The second fixation plate 32 includes a center opening 53 and two inletopenings 54 a and 54 b.

The center opening 53 is formed in a center region of the secondfixation plate 32, as viewed from the up-and-down direction. Further,the center opening 53 is circular as viewed from the up-and-downdirection. The center opening 53 is configured such that a centerportion of the center opening 53 coincides with the center portion ofthe center opening 38 of the spacer member 30.

The two inlet openings 54 a and 54 b are formed in a diagonal line thatconnects apexes 55 a and 55 c of the second fixation plate 32 in a statein which the center opening 53 is situated between the inlet openings 54a and 54 b, the apex 55 a being situated in back on the right, the apex55 c being situated in front on the left.

The inlet openings 54 a is formed between the center opening 53 and theapex 55 a. The inlet opening 54 a has a shape equal to the shape of theoutlet opening 47 a formed in the first fixation plate 28. The inletopening 54 a is formed such that a portion corresponding to therectangular opening is situated along the center opening 53 and suchthat a top of a portion corresponding to the semicircular opening isoriented toward the apex 55 a.

The inlet opening 54 b is formed between the center opening 53 and theapex 55 c. The inlet opening 54 b has a shape equal to the shape of theinlet opening 54 a. The inlet opening 54 b is formed such that a portioncorresponding to the rectangular opening is situated along the centeropening 53 and such that a top of a portion corresponding to thesemicircular opening is oriented toward the apex 55 c.

Further, as illustrated in FIG. 7 , the inlet opening 54 a is formedsuch that the inlet 50 a of the second resonance plate 31 is situatedinside of the inlet opening 54 a, as viewed from the up-and-downdirection. The inlet opening 54 b is formed such that the inlet 50 b ofthe second resonance plate 31 is situated inside of the inlet opening 54b, as viewed from the up-and-down direction.

Thus, the inlet opening 39 a of the spacer member 30 and the inletopening 54 a of the second fixation plate 32 are formed to overlap eachother, as viewed from the up-and-down direction. Further, the inletopening 39 b of the spacer member 30 and the inlet opening 54 b of thesecond fixation plate 32 are formed to overlap each other.

As illustrated in FIG. 9 , the first fixation plate 28 will have thesame configuration as the second fixation plate 32 when the firstfixation plate 28 is rotated 90 degrees, as viewed from the up-and-downdirection. In other words, the first fixation plate 28 and the secondfixation plate 32 have the same configuration with respect to anarrangement relationship of the openings, as viewed from the up-and-downdirection. Thus, two identical members are provided to have differentorientations. Accordingly, the two members can be respectively used asthe first fixation plate 28 and the second fixation plate 32.

Likewise, the first resonance plate 29 and the second resonance plate 31have the same configuration with respect to a positional relationship ofthe flexible portion (the first flexible portion 42/the second flexibleportion 49) formed in the center region of the resonance plate and thetwo openings (the inlets 50 a and 50 b/the outlets 43 a and 43 b). Thus,two identical members are provided to have different orientations.Accordingly, the two members are respectively used as the firstresonance plate 29 and the second resonance plate 31.

Identical members can be used by being provided to have differentorientations, as described above. This makes it possible to reduce coststo produce parts.

As illustrated in FIG. 8 , the first fixation plate 28, the firstresonance plate 29, the spacer member 30, the second resonance plate 31,and the second fixation plate 32 are stacked to be connected in theup-and-down direction.

The center opening 38 of the spacer member 30 is situated between thefirst flexible portion 42 of the first resonance plate 29 and the secondflexible portion 42 of the second resonance plate 31 to form the flowpath space S1.

A communication opening through which the center opening 38 illustratedin FIG. 9 communicates with the two inlet openings 39 a and 39 billustrated in FIG. 9 is formed as the inflow opening 3 illustrated inFIG. 1 . Further, a communication opening through which the centeropening 38 communicates with the two outlet openings 40 a and 40 b isformed as the outflow opening 4 illustrated in FIG. 1 .

Thus, in the present embodiment, the first resonance plate 29, thesecond resonance plate 31, and the spacer member 30 serve as a flow-pathspace forming portion.

As illustrated in FIG. 8 , the two inlet openings 39 a and 39 b of thespacer member 30 are situated between the first resonance plate 29 andthe second resonance plate 31 to form the intake space S2.

The inlets 50 a and 50 b are formed in a region, in the second resonanceplate 31, that covers the two inlet openings 39 a and 39 b of the spacermember 30. The inlets 50 a and 50 b enable the intake space S2 tocommunicate with the two inlet openings 54 a and 54 b of the secondfixation plate 32.

In the present embodiment, the first resonance plate 29, the secondresonance plate 31, and the spacer member 30 also serve as an intakespace forming portion that forms the intake space S2 through which theinflow opening 3 communicates with the inlets 50 a and 50 b.

As illustrated in FIG. 8 , the two outlet openings 40 a and 40 b of thespacer member 30 are situated between the first resonance plate 29 andthe second resonance plate 31 to form the discharge space S3.

The outlets 43 a and 43 b are formed in a region, in the first resonanceplate 29, that covers the two outlet openings 40 a and 40 b of thespacer member 30. The outlets 43 a and 43 b enable the discharge spaceS3 to communicate with the two outlet openings 47 a and 47 b of thefirst fixation plate 28.

In the present embodiment, the first resonance plate 29, the secondresonance plate 31, and the spacer member 30 also serve as a dischargespace forming portion that forms the discharge space S3 through whichthe outflow opening 4 communicates with the outlets 43 a and 43 b.

The fluid F is intaken into the intake space S2 through the two inletopenings 54 a and 54 b of the second fixation plate 32 passing throughthe inlets 50 a and 50 b. Through the inflow opening 3, the intakenfluid F flows into the flow path space S1 serving as a pump room.

The pump function causes the fluid F flowing into the flow path space S1to flow out of the flow path space S1 through the outflow opening 4, andto flow into the discharge space S3. The fluid F is discharged from thedischarge space S3 through the two outlet openings 47 a and 47 b of thefirst fixation plate 28 passing through the outlets 43 a and 43 b.

As illustrated in FIG. 8 , the first piezoelectric element 33 isconnected to an upper surface 57 of the first flexible portion 42. Theupper surface 57 of the first flexible portion 42 is a surface that isopposite to a surface of the first flexible portion 42 that faces thesecond flexible portion 49. The first piezoelectric element 33 isarranged within the center opening 46 of the first fixation plate 28.

As illustrated in FIG. 7 , the first piezoelectric element 33 iscircular as viewed from the up-and-down direction. The firstpiezoelectric element 33 is connected to the upper surface 57 of thefirst flexible portion 42 such that a center portion of the firstpiezoelectric element 33 coincides with the center portion 37 of thefirst flexible portion 42.

Further, the first piezoelectric element 33 is slightly smaller in sizethan the upper surface 57 of the first flexible portion 42, as viewedfrom the up-and-down direction. In other words, the first piezoelectricelement 33 is arranged in a region that is slightly smaller than anentire region of an upper surface of the flow path space S1, as viewedfrom the up-and-down direction.

As illustrated in FIG. 8 , the second piezoelectric element 34 isconnected to a lower surface 58 of the second flexible portion 49. Thelower surface 58 of the second flexible portion 49 is a surface that isopposite to a surface of the second flexible portion 49 that faces thefirst flexible portion 42. The second piezoelectric element 34 isarranged within the center opening 53 of the second fixation plate 32.

The second piezoelectric element 34 is circular as viewed from theup-and-down direction, where the shape of the second piezoelectricelement 34 is equal to the shape of the first piezoelectric element 33.Further, the second piezoelectric element 34 is arranged to overlap thefirst piezoelectric element 33, as viewed from the up-and-downdirection.

Thus, the second piezoelectric element 34 is connected to the lowersurface 58 of the second flexible portion 49 such that a center portionof the second piezoelectric element 34 coincides with the center portion51 of the second flexible portion 49.

Further, the second piezoelectric element 34 is slightly smaller in sizethan the lower surface 58 of the second flexible portion 49, as viewedfrom the up-and-down direction. In other words, the second piezoelectricelement 34 is arranged in a region that is slightly smaller than anentire region of a lower surface of the flow path space S1, as viewedfrom the up-and-down direction.

In the present embodiment, the first diaphragm is implemented by thefirst flexible portion 42 of the first resonance plate 29 and the firstpiezoelectric element 33. The second diaphragm is implemented by thesecond flexible portion 49 of the second resonance plate 31 and thesecond piezoelectric element 34.

As illustrated in FIG. 8 , the check valve 35 is provided to each of thetwo outlets 43 a and 44 b. The check valve 35 permits the fluid Fdischarged from the outlets 43 a and 44 b to flow into the outletopenings 47 a and 47 b. On the other hand, the check valve 35 preventsthe fluid F from flowing into the outlets 43 a and 44 b through theoutlet openings 47 a and 47 b.

When the check valve 35 is provided to each of the outlets 43 a and 44b, this makes it possible to prevent the fluid F from flowing backward,and thus to provide a high-level pump function.

A specific configuration of the check valve 35 is not limited, and anyconfiguration may be adopted. Note that an illustration of the checkvalve 35 is omitted in FIG. 7 .

Note that, in the present embodiment, the application of drive signals(alternate-current (AC) voltage) to the first piezoelectric element 33and the second piezoelectric element 34 makes it possible to cause thefirst diaphragm and the second diaphragm to oscillate in a highfrequency band with a high degree of ability to respond. In other words,the volume of the flow path space S1 is increased and decreasedrepeatedly (a pumping operation) at a very high speed.

Consequently, the level of the pump function is not decreased and a highperformance is maintained if no check valves are provided to the inlets50 a and 50 b. This makes it possible to reduce the number of checkvalues necessary, and thus to reduce costs for parts.

Of course, a check valve may be provided to each of the inlets 50 a and50 b.

In the present embodiment, the first resonance plate 29 corresponds toan embodiment of a first plate member. The second resonance plate 31corresponds to an embodiment of a second plate member. It can also besaid that the first resonance plate 29 corresponds to an embodiment ofthe second plate member, and the second resonance plate 31 correspondsto an embodiment of the first plate member.

The spacer member 30 corresponds to an embodiment of a spacer member.

The first piezoelectric element 33 and the second piezoelectric elementrespectively serve as drive mechanisms that respectively bend the firstflexible portion 42 and the second flexible portion 49. The drivecontrollers (not illustrated) also serving as the drive mechanismsrespectively apply drive signals (alternate-current (AC) voltages) tothe first piezoelectric element 33 and the second piezoelectric element34.

[Material]

In the present embodiment, a metallic material such as stainless orAlloy 42 is used for the first fixation plate 28, the first resonanceplate 29, the spacer member 30, the second resonance plate 31, and thesecond fixation plate 32. Of course, any other metallic material may beused. Further, any material, such as a plastic material, that is otherthan a metallic material may be used.

For example, the first flexible portion 42 of the first resonance plate29 may be made of, for example, a plastic material, and a portion of thefirst resonance plate 29 that is connected to the spacer member 30 andthe first fixation plate 28 may be made of a metallic material.

Likewise, the second flexible portion 49 of the second resonance plate31 may be made of, for example, a plastic material, and a portion of thesecond resonance plate 31 that is connected to the spacer member 30 andthe second fixation plate 32 may be made of a metallic material.

[Resonance Configuration]

A resonance configuration in which the first diaphragm (the firstflexible portion 42 and the first piezoelectric element 33) and thesecond diaphragm (the second flexible portion 49 and the secondpiezoelectric element 34) resonate with each other is adopted in thepresent embodiment. In other words, the first flexible portion 42 andthe second flexible portion 49 are configured to resonate with eachother.

Specifically, the configuration is made such that a resonance frequencyof the entirety of the first flexible portion 42 and the firstpiezoelectric element 33 is closer to a resonance frequency of theentirety of the second flexible portion 49 and the second piezoelectricelement 34.

[Production Method]

FIGS. 10 and 11 are sets of schematic diagrams used to describe a methodfor producing the fluid control apparatus 27.

First, the first fixation plate 28, the first resonance plate 29, thespacer member 30, the second resonance plate 31, and the second fixationplate 32, which are made of a metallic material, are created by anyprocessing technology such as etching or laser processing.

As illustrated in A and B of FIG. 10 , the created first fixation plate28, first resonance plate 29, spacer member 30, second resonance plate31, and second fixation plate 32 are stacked to be connected to eachother with a specified degree of accuracy in position.

In the present embodiment, the respective members are joined by diffusedjunction. Of course, any other methods may be used.

As illustrated in C of FIG. 10 , the first piezoelectric element 33 isconnected to the upper surface 57 of the first flexible portion 42through an adhesive 60. Further, the second piezoelectric element 34 isconnected to the lower surface 58 of the second flexible portion 49through an adhesive 61.

As illustrated in D of FIG. 10 , the first flexible portion 42 is curvedtoward the second flexible portion 49 to have a concave shape. Further,the second flexible portion 49 is curved toward the first flexibleportion 42 to have a concave shape.

As illustrated in D of FIG. 10 , the check valve 35 is provided to eachof the two outlets 43 a and 44 b.

FIG. 11 schematically illustrates an example of a method for connectingthe first piezoelectric element 33 to the first flexible portion 42 andconnecting and the second piezoelectric element 34 to the secondflexible portion 49.

As illustrated in A of FIG. 11 , the fluid control apparatus 27 beforebeing formed to have a concave shape, which is illustrated in B of FIG.10 , is placed on the holding fixture 23. First, the fluid controlapparatus 27 before being formed to have a concave shape is placed onthe holding fixture 23 such that the second fixation plate 32 is incontact with the holding fixture 23.

Further, as illustrated in A of FIG. 11 , pressure is applied to thefirst piezoelectric element 33 downward using the pressure fixture 24.Due to pressure being applied using the pressure fixture 24, the firstpiezoelectric element 33 and the first flexible portion 42 are deformedand curved toward the second flexible portion 49 to have a concaveshape. In this state, processing of hardening the adhesive 60 isperformed.

Accordingly, the fluid control apparatus 27 including the firstdiaphragm (the first flexible portion 42 and the first piezoelectricelement 33) formed to have a concave shape is created, as illustrated inB of FIG. 11 .

Note that the end portion 25 of the pressure fixture 24 is made of aflexible material such as a silicon rubber.

As illustrated in C of FIG. 11 , the fluid control apparatus 27 isturned upside down, and is placed on the holding fixture 23 such thatthe first fixation plate 28 is in contact with the holding fixture 23.

Then, as illustrated in C of FIG. 11 , pressure is applied to the secondpiezoelectric element 34 downward using the pressure fixture 24. Due topressure being applied using the pressure fixture 24, the secondpiezoelectric element 34 and the second flexible portion 49 are deformedand curved toward the first flexible portion 42 to have a concave shape.In this state, processing of hardening the adhesive 61 is performed.

Accordingly, the fluid control apparatus 27 including the seconddiaphragm (the second flexible portion 49 and the second piezoelectricelement 34) formed to have a concave shape is created, as illustrated inD of FIG. 11 .

A condition for applying pressure when the first piezoelectric element33 is bonded (hereinafter referred to as a first condition for applyingpressure) and a condition for applying pressure when the secondpiezoelectric element 34 is bonded (hereinafter referred to as a secondcondition for applying pressure) may each be set discretionarily. Forexample, a pressure-application force, a pressure-application time, atemperature, and the like may be set as appropriate such that each of anamount of concave of the first flexible portion 42 and an amount ofconcave of the second flexible portion 49 is a desired amount ofconcave.

For example, the first condition for applying pressure and the secondcondition for applying pressure are made equal. This makes it possibleto simplify production steps. Further, this makes it possible to make anamount of concave of the first flexible portion 42 and an amount ofconcave of the second flexible portion 49 equal.

As described above, a resonance frequency of a member is also affectedby a shape of the member. Thus, making the first condition for applyingpressure and the second condition for applying pressure equal results inbeing advantageous in enabling the resonance frequency of the firstdiaphragm (the first flexible portion 42 and the first piezoelectricelement 33) to be closer to the resonance frequency of the seconddiaphragm (the second flexible portion 49 and the second piezoelectricelement 34).

Of course, the first condition for applying pressure and the secondcondition for applying pressure may be set to be different from eachother. For example, the amount of concave of the first flexible portion42 and the amount of concave of the second flexible portion 49 may bedifferent from each other.

As illustrated in FIG. 11 , the present embodiment makes it possible tosimultaneously bond the first piezoelectric element 33 and deform thefirst flexible portion 42 such that the first flexible portion 42 has aconcave shape. In other words, when the first piezoelectric element 33is bonded, this enables the first flexible portion 42 to be deformed tohave a concave shape at the same time as the bonding of the firstpiezoelectric element 33.

Further, the present embodiment makes it possible to simultaneously bondthe second piezoelectric element 34 and deform the second flexibleportion 49 such that the second flexible portion 49 has a concave shape.In other words, when the second piezoelectric element 34 is bonded, thisenables the second flexible portion 49 to be deformed to have a concaveshape at the same time as the bonding of the second piezoelectricelement 34.

This results in being able to simplify steps of producing the fluidcontrol apparatus 27, and thus to shorten the time necessary for theproduction.

[Pumping Operation]

In the present embodiment, the drive controllers (not illustrated)respectively apply identical drive signals (alternate-current (AC)voltages) to the first piezoelectric element 33 and the secondpiezoelectric element 34.

Consequently, the first diaphragm (the first flexible portion 42 and thefirst piezoelectric element 33) and the second diaphragm (the secondflexible portion 49 and the second piezoelectric element 34) can berespectively bent upward and downward in synchronization with eachother.

Further, the first diaphragm (the first flexible portion 42 and thefirst piezoelectric element 33) and the second diaphragm (the secondflexible portion 49 and the second piezoelectric element 34) can berespectively bent downward and upward in synchronization with eachother.

In other words, in synchronization with each other, the two diaphragmsare respectively bent in a direction in which the volume of the flowpath space S1 is increased and in a direction in which the volume of theflow path space S1 is decreased. This results in being able to provide avery high-level pump function.

Further, in the present embodiment, a resonance configuration in whichthe first diaphragm and the second diaphragm resonate with each other isadopted. Thus, oscillation of each of the first diaphragm and the seconddiaphragm is maximized at the resonance frequency. This makes itpossible to provide a very high-level pump function.

FIG. 12 schematically illustrates an example of a flow of the fluid Fupon a pumping operation.

In the present embodiment, the fluid F intaken from the inlet 50 asituated in back on the right passes through the flow path space S1 tobe discharged from the outlet 43 b situated in front on the right.

Further, the fluid F intaken from the inlet 50 b situated in front onthe left passes through the flow path space S1 to be discharged from theoutlet 43 a situated in back on the left.

Of course, flow path designing is not limited thereto.

Note that inlets may be respectively formed in regions of the firstresonance plate 29 that respectively cover the two inlet openings 39 aand 39 b of the spacer member 30. Further, outlets may be respectivelyformed in regions of the second resonance plate 31 that respectivelycover the two outlet openings 40 a and 40 b of the spacer member 30.

[Decrease in Initial Volume]

FIG. 13 is a set of schematic diagrams used to describe an initialvolume, and FIG. 14 is a set of tables used to describe the initialvolume.

A of FIG. 13 schematically illustrates the flow path space S1 before thefirst flexible portion 42 and the second flexible portion 49 are formedto have a concave shape.

B of FIG. 13 schematically illustrates the flow path space S1 in thereference state.

C of FIG. 13 schematically illustrates the flow path space S1 duringdriving a pump.

As illustrated in A of FIG. 13 , the first flexible portion 42 and thesecond flexible portion 49 are arranged at the reference facing distanceH from each other.

As illustrated in B of FIG. 13 , the first flexible portion 42 is curvedby an amount of concave Z1 to have a concave shape. Further, the secondflexible portion 49 is curved by an amount of concave Z2 to have aconcave shape.

It is assumed that the first flexible portion 42 oscillates with anamplitude M1 by moving from the reference state in the up-and-downdirection, as illustrated in C of FIG. 13 . Further, it is assumed thatthe second flexible portion 49 oscillates with an amplitude M2 insynchronization with the first flexible portion 42.

It is assumed that a smallest facing distance between the first flexibleportion 42 and the second flexible portion 49 in the minimum volumestate is a minimum gap Gm.

In the present embodiment, the first flexible portion 42 and the secondflexible portion 49 are each formed to have a concave shape in thereference state, as illustrated in B of FIG. 13 . Thus, the initialvolume can be decreased. Therefore, the rate of volume variation can bemade higher, as represented by the formula (1). This makes it possibleto provide a high-level pump function.

Further, the reference facing distance H is maintained in the outerperipheral portion 11 of the flow path space S1. This makes it possibleto prevent the flow path resistances from being increased at the inflowopening 3 and the outflow opening 4. This results in not blocking a flowof the fluid F, that is, this results in being able to sufficientlyreduce a loss in flow path. Accordingly, a high-level pump function canbe provided.

Further, this makes it possible to suppress a reaction (a back pressure)that acts on each of the first flexible portion 42 and the secondflexible portion 49, and thus enables high-speed oscillation (a pistonmotion). This results in providing a high-level pump function.

For example, the first flexible portion 42 and the second flexibleportion 49 are each formed to have a size of a diameter of 9 mm.Further, two embodiments that are an embodiment in which the referencefacing distance H is 0.1 mm and an embodiment in which the referencefacing distance H is 0.2 mm, are provided.

Further, the first flexible portion 42 and the second flexible portion49 are designed such that the amount of concave Z1 of the first flexibleportion 42 and the amount of concave Z2 of the second flexible portion49 are equal.

In this case, the initial volume and the amount of concave have arelationship given in the tables of FIG. 14 .

In the case in which the reference facing distance H is 0.1 mm, theinitial volume is 6.361725 cubic millimeters when the amounts of concaveZ1 and Z2 are both zero (that is, before the first flexible portion 42and the second flexible portion 49 are each formed to have a concaveshape).

The initial volume is 5.725552 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.01 mm. Thus, the initial volume can bedecreased to 90% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.11-fold, which is calculated using the formula (1).

The initial volume is 5.089372 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.02 mm. Thus, the initial volume can bedecreased to 80% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.25-fold, which is calculated using the formula (1).

The initial volume is 3.816968 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.04 mm. Thus, the initial volume can bedecreased to 60% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.67-fold, which is calculated using the formula (1).

In the case in which the reference facing distance H is 0.2 mm, theinitial volume is 12.72345 cubic millimeters when the amounts of concaveZ1 and Z2 are both zero (that is, before the first flexible portion 42and the second flexible portion 49 are each formed to have a concaveshape).

The initial volume is 12.08728 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.01 mm. Thus, the initial volume can bedecreased to 95% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.05-fold, which is calculated using the formula (1).

The initial volume is 11.4511 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.02 mm. Thus, the initial volume can bedecreased to 90% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.11-fold, which is calculated using the formula (1).

The initial volume is 10.17869 cubic millimeters when the amounts ofconcave Z1 and Z2 are both 0.04 mm. Thus, the initial volume can bedecreased to 80% of the initial volume before the first flexible portion42 and the second flexible portion 49 are each formed to have a concaveshape. This makes it possible to increase the rate of volume variationabout 1.25-fold, which is calculated using the formula (1).

Note that it is favorable that the first flexible portion 42 not bebrought into contact with the second flexible portion 49 in thereference state illustrated in B of FIG. 13 . Thus, it is favorable that“reference facing distance H>amount of concave Z1+amount of concave Z2”.Note that a value obtained by “reference facing distance H−(amount ofconcave Z1+amount of concave Z2)” corresponds to a minimum facingdistance between the first flexible portion 42 and the second flexibleportion 49 in the reference state.

Further, it is favorable that, upon driving the fluid control apparatus1, the first flexible portion 42 not be brought into contact with thesecond flexible portion 49 in the minimum volume state.

Thus, it is favorable that “minimum gap Gm>0”, as illustrated in C ofFIG. 13 . Note that the minimum minimum gap Gm is represented by aformula indicated below.

minimum gap Gm=reference facing distance H−(amount of concave Z1+amountof concave Z2)−(amplitude M1/2+amplitude M2/2)  (3)

In other words, it is favorable that the minimum facing distance betweenthe center portion 15 of the upper surface member 6 and the centerportion 51 of the lower surface member 7 in the reference stateillustrated in B of FIG. 13 be greater than “amplitude M1/2+amplitudeM2/2” upon driving a pump.

Note that an optimal value of the amount of deformation of the firstflexible portion 42 differs depending on a relationship between flexuralrigidity of the first piezoelectric element 33, flexural rigidity of thefirst flexible portion 42, and a force to apply pressure to the firstpiezoelectric element 33 when the first piezoelectric element 33 isbonded. An optimal value of the amount of deformation of the secondflexible portion 49 differs depending on a relationship between flexuralrigidity of the second piezoelectric element 34, flexural rigidity ofthe second flexible portion 49, and a force to apply pressure to thesecond piezoelectric element 34 when the second piezoelectric element 34is bonded. Thus, it is also important to adjust a pressure-applicationforce in consideration of flexural rigidity of each member.

The configuration of the fluid control apparatus 27 according to thepresent embodiment is adopted, and the first flexible portion 42 and thesecond flexible portion 49 are each formed to have a diameter of 13 mm.Further, the reference facing distance H is set to 1 mm.

An alternate-current (AC) voltage of 30 Vpp is applied to each of thefirst piezoelectric element 33 and the second piezoelectric element 34to drive the fluid control apparatus 27.

This results in obtaining output having a maximum flow rate of 800ml/min or more, and a maximum pressure of 30 kPa or more. As describedabove, a small fluid control apparatus 27 exhibiting a very highperformance can be obtained.

Third Embodiment

FIG. 15 schematically illustrates examples of a configuration of a fluidcontrol apparatus according to a third embodiment.

A fluid control apparatus 64 of the present embodiment is different fromthe fluid control apparatus 27 according to the second embodiment inthat the second piezoelectric element 34 is not provided.

In other words, a piezoelectric element (the first piezoelectric element33) is connected only to the first flexible portion 42 in the presentembodiment. Further, due to oscillation of the first flexible portion42, the first flexible portion 42 and a second flexible portionoscillate with each other.

It can also be said that the fluid control apparatus 64 according to thepresent embodiment has a configuration obtained by combining the fluidcontrol apparatus 1 according to the first embodiment and the fluidcontrol apparatus 27 according to the second embodiment.

As illustrated in A of FIG. 15 , a second resonance plate 65 may be usedin the form of a flat plate, without being deformed to have a concaveshape. Thus, a second flexible portion 66 is in the form of a flatplate, without being formed to have a concave shape.

A thickness of the second flexible portion 66 corresponding to thesecond diaphragm is designed to be larger than a thickness of the firstflexible portion 42. This enables a resonance frequency of the entiretyof the first diaphragm (the first flexible portion 42 and the firstpiezoelectric element 33) to be closer to a resonance frequency of thesecond diaphragm (the second flexible portion 66). This makes itpossible to provide a resonance configuration, and thus to provide ahigh-level pump function due to a resonance effect.

As illustrated in B of FIG. 15 , the second flexible portion 66 of thesecond resonance plate 65 may be curved toward the first flexibleportion 42 to have a concave shape in the reference state. Thus, theinitial volume of the flow path space S1 can be decreased. Therefore,the rate of volume variation can be made higher, as represented by theformula (1). This makes it possible to provide a high-level pumpfunction.

Only one piezoelectric element is used in the fluid control apparatus 64according to the present embodiment, and this makes it possible toreduce costs for parts. Further, bonding of a piezoelectric element isonly performed once, and this makes it possible to simplify steps ofproducing the fluid control apparatus 64. Furthermore, this also makesit possible to shorten the time necessary for the production.

In the configuration illustrated in A of FIG. 15 , there is no need toform the second flexible portion 66 such that the second flexibleportion 66 has a concave shape. This results in being able to simplifyproduction steps, and thus to shorten the time necessary for theproduction. On the other hand, the configuration illustrated in B ofFIG. 15 provides a high-level pump function.

Other Embodiments

The present technology is not limited to the embodiments describedabove, and can achieve various other embodiments.

FIG. 16 schematically illustrates examples of a configuration of a fluidcontrol apparatus according to other embodiments.

In a fluid control apparatus 70 illustrated in FIG. 16 , a groove 73 isformed near an outer peripheral portion of each flexible portion (afirst flexible portion 71, a second flexible portion 72), as viewed fromthe up-and-down direction (the Z direction).

A portion near the outer peripheral portion is a region that is near theouter peripheral portion and situated further inward than the outerperipheral portion. For example, it is assumed that a width of a portionof a flexible portion that is largest when the flexible portion isviewed from the up-and-down direction is represented by a maximum width.The region near the outer peripheral portion can be determined on thebasis of the maximum width.

For example, a region situated at a distance of 25% of the maximum widththat is measured from the outer peripheral portion can be determined tobe the region near the outer peripheral portion. Of course, a regionsituated at a distance less than 25% of the maximum width may bedetermined to be the region near the outer peripheral portion.

Typically, the groove 73 is formed on all of the periphery along theouter peripheral portion of the flexible portion, as viewed from theup-and-down direction. Without being limited thereto, the groove 73 maybe formed intermittently at specified intervals.

Further, a plurality of the grooves 73 may be concentrically formed onall of the periphery of the flexible portion.

In the example illustrated in A of FIG. 16 , the groove 73 is formed onall of the periphery of a lower surface 74 of the first flexible portion71, as viewed from the up-and-down direction. Further, the groove 73 isformed on all of the periphery of an upper surface 75 of the secondflexible portion 72, as viewed from the up-and-down direction. Thegroove 73 formed in the first flexible portion 71 and the groove 73formed in the second flexible portion 72 coincide, as viewed from theup-and-down direction.

In the example illustrated in B of FIG. 16 , the groove 73 is formed onall of the periphery of an upper surface 76 of the first flexibleportion 71, as viewed from the up-and-down direction. Further, thegroove 73 is formed on all of the periphery of a lower surface 77 of thesecond flexible portion 72, as viewed from the up-and-down direction.The groove 73 formed in the first flexible portion 71 and the groove 73formed in the second flexible portion 72 coincide, as viewed from theup-and-down direction.

In the example illustrated in C of FIG. 16 , two grooves 73 areconcentrically formed on all of the periphery of the lower surface 74 ofthe first flexible portion 71, as viewed from the up-and-down direction.Further, two grooves 73 are concentrically formed on all of theperiphery of the upper surface 75 of the second flexible portion 72, asviewed from the up-and-down direction. Each of the two grooves 73 formedin the first flexible portion 71 and a corresponding one of the twogrooves 73 formed in the second flexible portion 72 coincide, as viewedfrom the up-and-down direction.

In the example illustrated in B of FIG. 16 , the groove 73 is formed onall of the periphery of each of the upper surface 76 and the lowersurface 74 of the first flexible portion 71, as viewed from theup-and-down direction. The two grooves 73 are concentrically formed, asviewed from the up-and-down direction.

Further, the groove 73 is formed on all of the periphery of each of thelower surface 77 and the upper surface 75 of the second flexible portion72, as viewed from the up-and-down direction. The two grooves 73 areconcentrically formed, as viewed from the up-and-down direction.

Each of the two grooves 73 formed in the first flexible portion 71 and acorresponding one of the two grooves 73 formed in the second flexibleportion 72 coincide, as viewed from the up-and-down direction.

The formation of the groove 73 results in easily deforming a portion inwhich the groove 73 is formed. This makes it possible to optimize anamount of deformation of the resonance plate and a shape of the deformedresonance plate, the deformation of the resonance plate being performeddue to pressure being applied upon bonding the piezoelectric element.

Further, stress caused in the flexible portion is increased in the outerperipheral portion of the piezoelectric element bonded to the flexibleportion. Thus, when the groove 73 is formed at a position based on theouter peripheral portion of the piezoelectric element, this makes itpossible to relax the stress caused in the flexible portion. Thisresults in being able to prevent the flexible portion from being broken.

Note that examples of the position based on the outer peripheral portionof the piezoelectric element include any positions determined on thebasis of the outer peripheral portion of the piezoelectric element.

The examples of the position based on the outer peripheral portioninclude a position that is situated in the outer peripheral portion ofthe piezoelectric element, as viewed from the up-and-down direction, aposition that is situated further outward than the outer peripheralportion of the piezoelectric element by a specified length, as viewedfrom the up-and-down direction, and a position that is situated furtherinward than the outer peripheral portion of the piezoelectric element bythe specified length, as viewed from the up-and-down direction. Notethat the specified length may be set discretionarily.

Of course, the examples of the position based on the outer peripheralportion of the piezoelectric element may include positions that are setusing any other methods.

Further, when the piezoelectric element is bonded to the flexibleportion using an adhesive, a variation in a resonance frequency of theentirety of the flexible portion and the piezoelectric element may occurdepending on an amount of the adhesive.

On the other hand, the appropriate formation of the groove 73 makes itpossible to reduce the variation in resonance frequency.

For example, the appropriate formation of the groove 73 easily enables aresonance frequency of the first flexible portion 71 and a resonancefrequency of the second flexible portion to be closer to each other.

A position at which the groove 73 is formed, the number of grooves 73, awidth and depth of the groove 73, and the like are not limited, and maybe designed discretionarily. These parameters have a close relationshipwith, for example, a resonance frequency of the resonance plate and anamount of deformation of the resonance plate after the piezoelectricelement is bonded. Thus, the parameters are desired to be determined inconsideration of the resonance frequency and the deformation amount.

A method for forming the groove 73 is also not limited. For example, anyprocessing technology such as etching or laser processing may be used.The groove 73 can be formed at the same time as formation of theresonance plate using, for example, etching or laser processing.

[Regarding Electronic Apparatus]

The application of the above-described fluid control apparatusesaccording to the present technology is not particularly limited, and,for example, the fluid control apparatuses can each be mounted on anelectronic apparatus. Each of the fluid control apparatuses enables airin an electronic apparatus to be discharged to the outside, or enablesair to be intaken into an electronic apparatus from the outside.

For example, each of the fluid control apparatuses can be used for thevarious purposes, such as using in a pressure generation device used bybeing worn on a human body, using in a small cooling device, or using ina pump used for a pneumatic actuator in, for example, a robot.

As a specific example, each of the fluid control apparatuses describedabove may be used as a cooling device that sprays fluid upon a heatingelement in an electronic apparatus to suppress heating. For example, thefluid control apparatus may be mounted on a mobile apparatus such as acellular phone to enable cooling.

Further, each of the fluid control apparatuses described above may bemounted on an electronic apparatus such as a tactile sense providingapparatus. This makes it possible to provide a pseudo sense of pressureor a pseudo tactile sense.

Furthermore, each of the fluid control apparatuses described above maybe mounted on an electronic apparatus such as a sphygmomanometer.

Moreover, each of the fluid control apparatuses described above may beapplied to an artificial muscle that is a telescopic actuator thatexpands and contracts by air pressure, the telescopic actuator beingmade of, for example, rubber.

Each of the fluid control apparatuses can be made smaller. Thus, anelectronic apparatus easily has the fluid control apparatus built in.Further, the application of the fluid control apparatus is veryadvantageous in making an electronic apparatus smaller. Furthermore,each of the fluid control apparatuses exhibits a high performance. Thismakes it possible to provide a high-performance electronic apparatus foreach purpose.

The respective configurations of the fluid control apparatus, theflow-path space forming portion, the intake space forming portion, thedischarge space forming portion, the flow path space, the intake space,the discharge space, the drive mechanism, the piezoelectric element, thegroove, and the like; the respective methods; and the like describedwith reference to the respective figures are merely embodiments, and anymodifications may be made thereto without departing from the spirit ofthe present technology. In other words, for example, any otherconfigurations or methods for purpose of practicing the presenttechnology may be adopted.

In the present disclosure, wording such as “substantially”, “almost”,and “approximately” is used as appropriate in order to facilitate theunderstanding of the description. On the other hand, whether the wordingsuch as “substantially”, “almost”, and “approximately” is used does notresult in a clear difference.

In other words, in the present disclosure, expressions, such as“center”, “middle”, “uniform”, “equal”, “similar”, “orthogonal”,“parallel”, “symmetric”, “extend”, “axial direction”, “columnar”,“cylindrical”, “ring-shaped”, and “annular” that define, for example, ashape, a size, a positional relationship, and a state respectivelyinclude, in concept, expressions such as “substantially thecenter/substantial center”, “substantially the middle/substantiallymiddle”, “substantially uniform”, “substantially equal”, “substantiallysimilar”, “substantially orthogonal”, “substantially parallel”,“substantially symmetric”, “substantially extend”, “substantially axialdirection”, “substantially columnar”, “substantially cylindrical”,“substantially ring-shaped”, and “substantially annular”.

For example, the expressions such as “center”, “middle”, “uniform”,“equal”, “similar”, “orthogonal”, “parallel”, “symmetric”, “extend”,“axial direction”, “columnar”, “cylindrical”, “ring-shaped”, and“annular” also respectively include states within specified ranges (suchas a range of +/−10%), with expressions such as “exactly thecenter/exact center”, “exactly the middle/exactly middle”, “exactlyuniform”, “exactly equal”, “exactly similar”, “completely orthogonal”,“completely parallel”, “completely symmetric”, “completely extend”,“fully axial direction”, “perfectly columnar”, “perfectly cylindrical”,“perfectly ring-shaped”, and “perfectly annular” being respectively usedas references.

Thus, an expression that does not include the wording such as“substantially”, “almost”, and “approximately” can also include, inconcept, a possible expression including the wording such as“substantially”, “almost”, and “approximately”. Conversely, a stateexpressed using the expression including the wording such as“substantially”, “almost”, and “approximately” may include a state of“exactly/exact”, “completely”, “fully”, or “perfectly”.

In the present disclosure, an expression using “-er than” such as “beinglarger than A” and “being smaller than A” comprehensively includes, inconcept, an expression that includes “being equal to A” and anexpression that does not include “being equal to A”. For example, “beinglarger than A” is not limited to the expression that does not include“being equal to A”, and also includes “being equal to or greater thanA”. Further, “being smaller than A” is not limited to “being less thanA”, and also includes “being equal to or less than A”.

When the present technology is carried out, it is sufficient if aspecific setting or the like is adopted as appropriate from expressionsincluded in “being larger than A” and expressions included in “beingsmaller than A”, in order to provide the effects described above.

At least two of the features of the present technology described abovecan also be combined. In other words, the various features described inthe respective embodiments may be combined discretionarily regardless ofthe embodiments. Further, the various effects described above are notlimitative but are merely illustrative, and other effects may beprovided.

Note that the present technology may also take the followingconfigurations.

(1) A fluid control apparatus, including:

-   -   a flow-path space forming portion that includes a flexible        portion that have flexibility, and a facing portion that faces        the flexible portion, the flow-path space forming portion        forming a flow path space between the flexible portion and the        facing portion, the flow path space being a flow path of fluid;    -   an inflow opening that is provided to an outer peripheral        portion of the flow path space, as viewed from a facing        direction in which the flexible portion and the facing portion        face each other, the inflow opening being an opening through        which the fluid flows into the flow path space;    -   an outflow opening that is provided to a portion, in the outer        peripheral portion of the flow path space, that is different        from a portion, in the outer peripheral portion of the flow path        space, that is provided with the inflow opening, as viewed from        the facing direction, the outflow opening being an opening        through which the fluid flows out of the flow path space; and    -   a drive mechanism that bends the flexible portion to increase or        decrease the volume of the flow path space,    -   the flexible portion being configured such that at least a        portion of a region of the flexible portion is curved toward the        facing portion to have a concave shape in a reference state in        which the flexible portion is not bent by the drive mechanism,        the region of the flexible portion being situated further inward        than the outer peripheral portion of the flow path space, as        viewed from the facing direction.        (2) The fluid control apparatus according to (1), in which    -   the flexible portion is configured such that a center portion of        the flexible portion as viewed from the facing direction is        curved toward the facing portion to have a concave shape in the        reference state.        (3) The fluid control apparatus according to (1) or (2), in        which    -   the flexible portion has a shape obtained by a plate member        being deformed and curved toward the facing portion to have a        concave shape in the reference state.        (4) The fluid control apparatus according to any one of (1) to        (3), in which    -   the drive mechanism bends the flexible portion such that a        concave portion of the flexible portion in the reference state        is moved by a largest distance in the facing direction.        (5) The fluid control apparatus according to any one of (1) to        (4), in which    -   the drive mechanism includes a piezoelectric element that is        connected to a certain surface of the flexible portion that is        situated opposite to another surface of the flexible portion        that faces the facing portion.        (6) The fluid control apparatus according to any one of (1) to        (5), in which    -   when the flexible portion is a first flexible portion, the        facing portion is a second flexible portion that has        flexibility,    -   the drive mechanism bends the second flexible portion, and    -   the second flexible portion is configured such that at least a        portion of a region of the second flexible portion is curved        toward the first flexible portion to have a concave shape in the        reference state, the region of the second flexible portion being        situated further inward than the outer peripheral portion of the        flow path space, as viewed from the facing direction.        (7) The fluid control apparatus according to (6), in which    -   the first flexible portion and the second flexible portion are        configured to resonate with each other.        (8) The fluid control apparatus according to (7), in which    -   the drive mechanism includes        -   a first piezoelectric element that is connected to a certain            surface of the first flexible portion that is opposite to            another surface of the first flexible portion that faces the            second flexible portion, and        -   a second piezoelectric element that is connected to a            certain surface of the second flexible portion that is            opposite to another surface of the second flexible portion            that faces the first flexible portion, and    -   the drive mechanism is configured such that a resonance        frequency of the entirety of the first flexible portion and the        first piezoelectric element is closer to a resonance frequency        of the entirety of the second flexible portion and the second        piezoelectric element.        (9) The fluid control apparatus according to any one of (1) to        (5), in which    -   when the flexible portion is a first flexible portion, the        facing portion is a second flexible portion that has        flexibility, and    -   the first flexible portion and the second flexible portion are        configured to resonate with each other.        (10) The fluid control apparatus according to (9), in which    -   the drive mechanism includes a piezoelectric element that is        connected to a certain surface of the first flexible portion        that is situated opposite to another surface of the first        flexible portion that faces the second flexible portion, and    -   the drive mechanism is configured such that a resonance        frequency of the second flexible portion is closer to a        resonance frequency of the entirety of the first flexible        portion and the first piezoelectric element.        (11) The fluid control apparatus according to (10), in which    -   the second flexible portion has a larger thickness than the        first flexible portion.        (12) The fluid control apparatus according to any one of (8) to        (11), in which    -   the second flexible portion is configured such that the at least        the portion of the region of the second flexible portion is        curved toward the first flexible portion to have a concave shape        in the reference state, the region of the second flexible        portion being situated further inward than the outer peripheral        portion of the flow path space, as viewed from the facing        direction.        (13) The fluid control apparatus according to any one of (1) to        (12), in which    -   the flexible portion includes a groove that is formed near an        outer peripheral portion of the flexible portion, as viewed from        the facing direction.        (14) The fluid control apparatus according to (13), in which    -   the drive mechanism includes a piezoelectric element that is        connected to a certain surface of the flexible portion that is        situated opposite to another surface of the flexible portion        that faces the facing portion, and    -   the groove is formed at a position based on an outer peripheral        portion of the piezoelectric element, as viewed from the facing        direction.        (15) The fluid control apparatus according to any one of (1) to        (14), further including:    -   an inlet through which the fluid is intaken into the fluid        control apparatus;    -   an intake space forming portion that forms an intake space        through which the inlet and the inflow opening communicate with        each other;    -   an outlet through which the fluid is discharged from the fluid        control apparatus; and    -   a discharge space forming portion that forms a discharge space        through which the outlet and the outflow opening communicate        with each other.        (16) The fluid control apparatus according to any one of (1) to        (15), in which    -   the flow-path space forming portion includes        -   a first plate member that is made of a metallic material and            includes the flexible portion in a center region of the            first plate member, as viewed from the facing direction,        -   a second plate member that is made of a metallic material            and includes the facing portion in a center region of the            second plate member, as viewed from the facing direction,            and        -   a spacer member that has a specified thickness and includes            an opening in a center region of the spacer member, as            viewed from the facing direction, the spacer member being            arranged between the first plate member and the second plate            member, the spacer member being joined to the first plate            member and to the second plate member using diffused            junction.            (17) The fluid control apparatus according to (16), in which    -   the spacer member includes        -   an inlet opening that is configured to communicate with an            outer peripheral portion of the center opening, and        -   an outlet opening that is configured to communicate with the            outer peripheral portion of the center opening, the outlet            opening being provided to a portion, in the spacer member,            that is different from a portion, in the spacer member, that            is provided with the inlet opening.            (18) The fluid control apparatus according to (17), in which    -   an inlet through which the fluid is intaken into the fluid        control apparatus is formed in at least one of a region, in the        first plate member, that covers the inlet opening, or a region,        in the second plate member, that covers the inlet opening, and    -   an outlet through which the fluid is discharged from the fluid        control apparatus is formed in at least one of a region, in the        first plate member, that covers the outlet opening, or a region,        in the second plate member, that covers the outlet opening.        (19) An electronic apparatus, including    -   a fluid control apparatus that includes        -   a flow-path space forming portion that includes a flexible            portion that have flexibility, and a facing portion that            faces the flexible portion, the flow-path space forming            portion forming a flow path space between the flexible            portion and the facing portion, the flow path space being a            flow path of fluid,        -   an inflow opening that is provided to an outer peripheral            portion of the flow path space, as viewed from a facing            direction in which the flexible portion and the facing            portion face each other, the inflow opening being an opening            through which the fluid flows into the flow path space,        -   an outflow opening that is provided to a portion, in the            outer peripheral portion of the flow path space, that is            different from a portion, in the outer peripheral portion of            the flow path space, that is provided with the inflow            opening, as viewed from the facing direction, the outflow            opening being an opening through which the fluid flows out            of the flow path space, and        -   a drive mechanism that bends the flexible portion to            increase or decrease the volume of the flow path space,    -   the flexible portion being configured such that at least a        portion of a region of the flexible portion is curved toward the        facing portion to have a concave shape in a reference state in        which the flexible portion is not bent by the drive mechanism,        the region of the flexible portion being situated further inward        than the outer peripheral portion of the flow path space, as        viewed from the facing direction.

REFERENCE SIGNS LIST

-   -   Gm minimum gap    -   H reference facing distance    -   M amplitude    -   S1 flow path space    -   S2 intake space    -   S3 discharge space    -   Z amount of concave    -   1, 27, 64, 70 fluid control apparatus    -   2 flow-path space forming portion    -   3 inflow opening    -   4 outflow opening    -   5 drive mechanism    -   6 upper surface member    -   7 lower surface member    -   8 a, 8 b, 30 spacer member    -   11 outer peripheral portion of flow path space    -   15 center portion of upper surface member    -   17 piezoelectric element    -   29 first resonance plate    -   31, 65 second resonance plate    -   33 first piezoelectric element    -   34 second piezoelectric element    -   37 center portion of first flexible portion    -   42, 71 first flexible portion    -   43 a, 43 b outlet    -   49, 66, 72 second flexible portion    -   50 b inlet    -   51 center portion of second flexible portion    -   73 groove

1. A fluid control apparatus, comprising: a flow-path space formingportion that includes a flexible portion that have flexibility, and afacing portion that faces the flexible portion, the flow-path spaceforming portion forming a flow path space between the flexible portionand the facing portion, the flow path space being a flow path of fluid;an inflow opening that is provided to an outer peripheral portion of theflow path space, as viewed from a facing direction in which the flexibleportion and the facing portion face each other, the inflow opening beingan opening through which the fluid flows into the flow path space; anoutflow opening that is provided to a portion, in the outer peripheralportion of the flow path space, that is different from a portion, in theouter peripheral portion of the flow path space, that is provided withthe inflow opening, as viewed from the facing direction, the outflowopening being an opening through which the fluid flows out of the flowpath space; and a drive mechanism that bends the flexible portion toincrease or decrease the volume of the flow path space, the flexibleportion being configured such that at least a portion of a region of theflexible portion is curved toward the facing portion to have a concaveshape in a reference state in which the flexible portion is not bent bythe drive mechanism, the region of the flexible portion being situatedfurther inward than the outer peripheral portion of the flow path space,as viewed from the facing direction.
 2. The fluid control apparatusaccording to claim 1, wherein the flexible portion is configured suchthat a center portion of the flexible portion as viewed from the facingdirection is curved toward the facing portion to have a concave shape inthe reference state.
 3. The fluid control apparatus according to claim1, wherein the flexible portion has a shape obtained by a plate memberbeing deformed and curved toward the facing portion to have a concaveshape in the reference state.
 4. The fluid control apparatus accordingto claim 1, wherein the drive mechanism bends the flexible portion suchthat a concave portion of the flexible portion in the reference state ismoved by a largest distance in the facing direction.
 5. The fluidcontrol apparatus according to claim 1, wherein the drive mechanismincludes a piezoelectric element that is connected to a certain surfaceof the flexible portion that is situated opposite to another surface ofthe flexible portion that faces the facing portion.
 6. The fluid controlapparatus according to claim 1, wherein when the flexible portion is afirst flexible portion, the facing portion is a second flexible portionthat has flexibility, the drive mechanism bends the second flexibleportion, and the second flexible portion is configured such that atleast a portion of a region of the second flexible portion is curvedtoward the first flexible portion to have a concave shape in thereference state, the region of the second flexible portion beingsituated further inward than the outer peripheral portion of the flowpath space, as viewed from the facing direction.
 7. The fluid controlapparatus according to claim 6, wherein the first flexible portion andthe second flexible portion are configured to resonate with each other.8. The fluid control apparatus according to claim 7, wherein the drivemechanism includes a first piezoelectric element that is connected to acertain surface of the first flexible portion that is opposite toanother surface of the first flexible portion that faces the secondflexible portion, and a second piezoelectric element that is connectedto a certain surface of the second flexible portion that is opposite toanother surface of the second flexible portion that faces the firstflexible portion, and the drive mechanism is configured such that aresonance frequency of the entirety of the first flexible portion andthe first piezoelectric element is closer to a resonance frequency ofthe entirety of the second flexible portion and the second piezoelectricelement.
 9. The fluid control apparatus according to claim 1, whereinwhen the flexible portion is a first flexible portion, the facingportion is a second flexible portion that has flexibility, and the firstflexible portion and the second flexible portion are configured toresonate with each other.
 10. The fluid control apparatus according toclaim 9, wherein the drive mechanism includes a piezoelectric elementthat is connected to a certain surface of the first flexible portionthat is situated opposite to another surface of the first flexibleportion that faces the second flexible portion, and the drive mechanismis configured such that a resonance frequency of the second flexibleportion is closer to a resonance frequency of the entirety of the firstflexible portion and the first piezoelectric element.
 11. The fluidcontrol apparatus according to claim 10, wherein the second flexibleportion has a larger thickness than the first flexible portion.
 12. Thefluid control apparatus according to claim 8, wherein the secondflexible portion is configured such that the at least the portion of theregion of the second flexible portion is curved toward the firstflexible portion to have a concave shape in the reference state, theregion of the second flexible portion being situated further inward thanthe outer peripheral portion of the flow path space, as viewed from thefacing direction.
 13. The fluid control apparatus according to claim 1,wherein the flexible portion includes a groove that is formed near anouter peripheral portion of the flexible portion, as viewed from thefacing direction.
 14. The fluid control apparatus according to claim 13,wherein the drive mechanism includes a piezoelectric element that isconnected to a certain surface of the flexible portion that is situatedopposite to another surface of the flexible portion that faces thefacing portion, and the groove is formed at a position based on an outerperipheral portion of the piezoelectric element, as viewed from thefacing direction.
 15. The fluid control apparatus according to claim 1,further comprising: an inlet through which the fluid is intaken into thefluid control apparatus; an intake space forming portion that forms anintake space through which the inlet and the inflow opening communicatewith each other; an outlet through which the fluid is discharged fromthe fluid control apparatus; and a discharge space forming portion thatforms a discharge space through which the outlet and the outflow openingcommunicate with each other.
 16. The fluid control apparatus accordingto claim 1, wherein the flow-path space forming portion includes a firstplate member that is made of a metallic material and includes theflexible portion in a center region of the first plate member, as viewedfrom the facing direction, a second plate member that is made of ametallic material and includes the facing portion in a center region ofthe second plate member, as viewed from the facing direction, and aspacer member that has a specified thickness and includes an opening ina center region of the spacer member, as viewed from the facingdirection, the spacer member being arranged between the first platemember and the second plate member, the spacer member being joined tothe first plate member and to the second plate member using diffusedjunction.
 17. The fluid control apparatus according to claim 16, whereinthe spacer member includes an inlet opening that is configured tocommunicate with an outer peripheral portion of the center opening, andan outlet opening that is configured to communicate with the outerperipheral portion of the center opening, the outlet opening beingprovided to a portion, in the spacer member, that is different from aportion, in the spacer member, that is provided with the inlet opening.18. The fluid control apparatus according to claim 17, wherein an inletthrough which the fluid is intaken into the fluid control apparatus isformed in at least one of a region, in the first plate member, thatcovers the inlet opening, or a region, in the second plate member, thatcovers the inlet opening, and an outlet through which the fluid isdischarged from the fluid control apparatus is formed in at least one ofa region, in the first plate member, that covers the outlet opening, ora region, in the second plate member, that covers the outlet opening.19. An electronic apparatus, comprising a fluid control apparatus thatincludes a flow-path space forming portion that includes a flexibleportion that have flexibility, and a facing portion that faces theflexible portion, the flow-path space forming portion forming a flowpath space between the flexible portion and the facing portion, the flowpath space being a flow path of fluid, an inflow opening that isprovided to an outer peripheral portion of the flow path space, asviewed from a facing direction in which the flexible portion and thefacing portion face each other, the inflow opening being an openingthrough which the fluid flows into the flow path space, an outflowopening that is provided to a portion, in the outer peripheral portionof the flow path space, that is different from a portion, in the outerperipheral portion of the flow path space, that is provided with theinflow opening, as viewed from the facing direction, the outflow openingbeing an opening through which the fluid flows out of the flow pathspace, and a drive mechanism that bends the flexible portion to increaseor decrease the volume of the flow path space, the flexible portionbeing configured such that at least a portion of a region of theflexible portion is curved toward the facing portion to have a concaveshape in a reference state in which the flexible portion is not bent bythe drive mechanism, the region of the flexible portion being situatedfurther inward than the outer peripheral portion of the flow path space,as viewed from the facing direction.